From reauthorizing the construction of contentious pipeline projects to halting the progression of former President Barack Obama's pending regulations, many of President Trump's early executive actions have sparked immediate changes in the federal government.

Others, such as his memorandum to the Department of Commerce asking for a review about how to require the use of U.S. steel when building pipelines, merely paved the way for potential future actions.

"The whole point of an executive order is that it can be implemented immediately," said Tommy Binion, director of policy outreach at the Heritage Foundation. "There are broader policies that some of the executive orders indicate are coming, but as far as what's actually contained in the executive orders themselves, we should expect that to be immediate."

While Trump's sweeping policy changes are consistent with his campaign promises, they won't all lead to immediate shifts and they don't all carry the same significance.

Here's what we can actually expect to see from 20 of the president's first executive actions.

Policies that will change immediately

1. Extreme vetting

Trump delivered on one of his most contentious campaign promises on Jan. 27 when he signed an executive order temporarily suspending refugee programs for 120 days and immigration from seven Middle Eastern countries from 90 days.

Those countries — Iran, Iraq, Somalia, Sudan, Yemen, Libya and Syria — may have to start providing additional information about citizens who wish to enter the U.S. under the stricter vetting standards Trump requested in his executive order.

The president also indefinitely halted the flow of refugees from Syria.

The suspensions outlined in Trump's controversial order took effect immediately.

However, a federal judge temporarily halted the restrictions on Feb. 3 in a high-profile court case filed in Seattle. The Trump Justice Department quickly appealed the ruling in the 9th Circuit Court of Appeals, but the administration's efforts to get the Seattle judge's stay overturned on an emergency basis was denied. Now, the Justice Department and the Washington state attorney general, who brought the suit that yielded the pause in enforcement of the travel ban, must each submit more detailed arguments.

2. Speeding up environmental reviews for high priority projects

Trump signed an executive order on Jan. 24 that would give his White House the authority to identify, at the request of governors or agency heads, which infrastructure projects would be considered "high priority."

His administration would then use "expedited procedures and deadlines for completion of environmental reviews and approvals for such projects," according to the order.

Unlike the presidential memo on permitting processes that Trump signed on Jan. 24, the environmental review action came in the form of an executive order and will spark changes more quickly.

3. Border wall

Trump signed an executive order on Jan. 25 calling for "the immediate construction of a physical wall on the southern border."

The order also instructed the Department of Homeland Security to direct resources toward the expansion of detention facilities near the border for illegal immigrants.

Although it will take effect right away, Republican lawmakers have suggested they could look at ways to appropriate additional funds toward building the border wall.

4. Sanctuary cities

Another immigration-related executive order involved the enforcement of laws already on the books.

Trump ordered border patrol agents and immigration officials to begin deporting undocumented immigrants who have committed crimes, regardless of whether they reside in areas known as "sanctuary cities," where immigration laws are not typically enforced.

In order to pressure sanctuary cities into complying with the order, Trump threatened to suspend federal grants to those areas until the law is enforced.

The new marching orders for the Department of Homeland Security, which houses border patrol, should take effect immediately.

5. TPP withdrawal

Trump's move to withdraw the United States from the Trans-Pacific Partnership, a deeply unpopular trade agreement, will effectively end the deal's chances of becoming reality in Congress.

TPP had already become a toxic agreement, with lawmakers on both sides of the aisle under pressure from voters to ditch the deal.

6. National Security Council tweaks

Trump signed on Jan. 28 what initially appeared to be a routine restructuring of his National Security Council.

Trump's reshuffling of the National Security Council ultimately ruffled some feathers in the security community because it removed the chairman of the Joint Chiefs of Staff and the director of national intelligence from those who regularly attend its meetings. Those officials are welcome to attend any meeting they want, White House press secretary Sean Spicer clarified on Jan. 30.

The controversial memo also added White House chief strategist Stephen Bannon as a regular member.

The moves added to Trump's efforts to remake the way the United States approaches national security and foreign policy.

7. Regulation limits

An order Trump signed on Jan. 30 will force the administration to roll back two regulations for every new one his agencies enact.

Trump had promised to implement such a policy shortly after getting elected. The president has repeatedly vowed to cut regulations across the board, from environmental restrictions to labor rules.

During a meeting with manufacturers shortly after taking office, Trump said he would consider taking as much as 75 percent of existing regulations off the books.

Policies that are possible later

8. Obamacare

Within hours of taking the oath of office, Trump put his signature on a pair of executive actions designed to go after policies his predecessor had put in place. One was an order instructing federal agencies to stop enforcing aspects of Obamacare.

The order told federal agencies to delay the implementation of pending provisions and exempt fees or penalties wherever possible while awaiting full repeal of the law.

Marshall Kapp, an expert on healthcare policy at Florida State University, said the order was more symbolic than substantive.

Because Congress must pass legislation to enact any real changes to the Affordable Care Act, Kapp said the executive order Trump signed on Jan. 20 was "more for public consumption."

Kapp said Trump could have just as easily asked his appointees to use their existing discretion to thwart Obamacare in a phone conversation or face-to-face meeting.

The executive order, however, sends voters a message about the president's commitment to dismantling Obamacare.

9. Pipes made with U.S. steel

Trump signed an executive action on Jan. 24 that the White House said would pave the way for builders to use only American steel in pipeline construction projects.

But that action was merely a presidential memo instructing his commerce secretary to review ways such a policy could be feasible in the future.

Wilbur Ross, who has not yet been confirmed to the commerce secretary post to which he was nominated, will have 180 days to put together a plan to require new, updated or expanded pipeline projects to use American steel and equipment "to the maximum extent possible and to the extent permitted by law."

10. Streamlining permits

Similarly, Trump's executive action on manufacturing permits came in the form of a memo to Ross.

This presidential memorandum was aimed at "reducing regulatory burdens for domestic manufacturing," but it didn't totally clear the way for businesses to obtain permits with no strings attached.

Instead, Trump requested a report from Ross that would "identify priority actions as well as recommended deadlines for completing actions." The memo did not recommend deadlines for those actions, which the White House said would make it easier for factories to get up and running.

According to the memo, "the report also may include recommendations for any necessary changes to existing regulations or statutes, as well as actions to change policies, practices, or procedures that can be taken immediately under existing authority."

Changes to regulations, however, can take months and are subject to legal challenges that can delay the process even further.

11. Dakota Access Pipeline

Trump signed a pair of presidential memos that cleared the way for two controversial pipeline projects to move forward.

The Dakota Access Pipeline, most of which has already been built, had sparked intense protests from the Stand Rock Sioux Tribe in North Dakota due to the Native American group's proximity to a planned portion of the pipeline.

Under Obama, the U.S. Army Corps of Engineers suspended construction of the Dakota Access Pipeline amid increasingly visible and fierce protests against it.

Trump's memo instructed the Army Corps of Engineers to "review and approve in an expedited manner" requests to build and operate the remaining sections of the Dakota Access Pipeline. Although he ordered the project to move forward, that review process still has to occur before builders can get back on the job.

12. Keystone XL Pipeline

The Keystone XL Pipeline was another highly symbolic project that withered under the Obama administration.

Trump revived it on Jan. 24 by inviting TransCanada, the Canadian company that had sought permission to build Keystone XL, to reapply for a permit to construct the contested section of the pipeline.

TransCanada did so on Jan. 26.

13. Military rebuild

Trump signed a presidential memo on Jan. 27 that asked Defense Secretary Jim Mattis to prepare a report within 60 days that would map out ways the military could hit increased levels of readiness by 2019.

The president has frequently promised to rebuild the armed forces, which he said his predecessor depleted.

But the memo outlined few specifics about what form the military rebuild could take, and it doesn't ask the Pentagon to achieve those changes for two years. Such an effort will likely be slow and costly as branches of the military recruit additional personnel and build new planes, ships and equipment.

Trump also instructed Mattis to initiate a review of the country's nuclear posture to ensure that the nuclear arsenal is "modern, robust, flexible, resilient, ready and appropriately tailored to deter 21st century threats and deter our allies."

14. Plan to defeat the Islamic State

Trump issued a presidential memo on Jan. 28 that called on members of his administration to put together a plan for defeating the Islamic State.

Rather than instructing his agencies to take action related to the terrorist group, Trump merely asked them to compile a list of actions they could take in the future.

15. Lobbying ban

Trump's five-year lobbying ban on officials who leave his administration will take effect retroactively, applying only to those who decamp for other jobs in the future.

It is meant to prevent his staff from cashing in on their administration jobs for five years after their departures. The executive order, which Trump signed on Jan. 28, also permanently restricts staffers' ability to lobby for a foreign government.

The precise effect of the order remains to be seen. Lobbying can often be accomplished in hard-to-detect ways, and the potency of the order may not be tested for years.

16. Investment rule

Delaying an Obama-era financial services regulation, Trump signed a memo to the Department of Labor on Feb. 3 that called for a review of the Fiduciary Duty Rule, which the previous administration had finalized in April of last year.

That rule attempted to address potential conflicts of interest by requiring financial advisors who are paid on commission to steer their clients toward the most appropriate investments, not just toward acceptable investments that might provide higher commissions. Democrats have accused Republicans of exposing Americans' retirement savings to Wall Street greed, while Republicans in favor of Trump's thinking have said the fiduciary rule may shut out small businesses or less-wealthy individuals as a result of forcing brokers to comply with a burdensome regulation.

Trump's memo will stall the implementation of the Fiduciary Duty Rule, which was slated for April 10, while the next labor secretary weighs whether the rule would spawn more litigation or disrupt the retirement services industry.

17. Reviewing Wall Street regulations

An executive order Trump signed on Feb. 3 instructed the treasury secretary to review Wall Street regulations and determine whether those restrictions adhere to a set of "Core Principles" outlined in the order.

Those principles included moves to "prevent taxpayer-funded bailouts" and give individual investors the ability "to make independent financial decisions and informed choices in the marketplace."

Critics quickly charged that Trump was preparing to water down the Dodd-Frank Act, a set of financial industry regulations Congress enacted after the 2008 financial crisis.

Trump and his allies have repeatedly blasted Dodd-Frank, arguing the legislation prevents community banks from lending to small businesses by forcing them to comply with the same burdensome rules that apply to big banks.

Routine orders

18. Hiring freeze

Former Presidents Jimmy Carter, Ronald Reagan and George W. Bush instituted federal hiring freezes during their presidencies, so Trump's move to do so is not unprecedented.

The president has signaled his intention to cut the federal workforce, and could potentially accomplish that by maintaining the freeze and allowing attrition to reduce its size.

The hiring freeze does not apply to the military or some public health positions at the Department of Veterans Affairs.

19. Regulatory freeze

A regulatory freeze is a routine way for new administrations to halt the progression of rules commissioned by previous presidents.

Obama issued a temporary regulatory freeze when he came into office, and Trump signed one as well.

In fact, he made the move a top priority, tackling the freeze shortly after taking the oath of office on Jan. 20. Trump has frequently focused on deregulation as a key step toward creating a more business-friendly climate in the U.S.

20. Mexico City policy

Trump continued a tradition, begun by Reagan and continued by Bush, of reinstituting a practice known as the Mexico City policy.

According to the Mexico City policy, groups that perform or promote abortions overseas do not receive federal funds.