Conservatives are outraged that President Obama is threatening to use his executive authority to shelter undocumented foreigners from deportation now that immigration reform seems dead this year.

But whether they like it or not, existing immigration laws give the president vast discretion to temporarily legalize an unlimited number of foreigners.

The president hasn’t yet said exactly what he’ll do, but some reports suggest that he might “defer action” against undocumented aliens who are parents of U.S. citizens or have held steady employment. This means that instead of being hunted down and deported, they’d be officially notified they won’t be targeted for some period during which they would be allowed to work. This is what he did with illegals brought into the country as minors after Congress failed to pass the Dream Act. His new dispensation could potentially cover as many as 5 million undocumented workers.

This prompted New York Times columnist Ross Douthat to accuse the president of “domestic Caesarism.” Granting temporary legal status by executive fiat, he insisted, would be “an extraordinary abuse of office” and tantamount to rewriting existing immigration laws.

But Margaret Stock, a Republican immigration lawyer and a Federalist Society member, notes that such accusations don’t appreciate that all this is fully authorized by those laws. "The Immigration and Nationality Act and other laws are chock-full of huge grants of statutory authority to the president,” she explains, a point also emphasized by the nonpartisan Congressional Research Service in its 2013 brief. “Congress gave the president all these powers, and now they are upset because he wants to use them. Other presidents have used the same authority in the past without an outcry.”

Most accept that the discretion that the executive branch enjoys in enforcing immigration law is as broad as what prosecutors enjoy in criminal law. And the reason is the same: More offenders than means to prosecute makes drastic prioritization necessary. But conservatives argue that failing to prosecute is not the same as legalizing, the further step that the president would be taking by issuing work permits.

But this is incorrect. Until Congress actually passes a law issuing permanent residency, nothing that Obama is suggesting would prevent future presidents from stripping these folks of their temporary status and deporting them. So an executive action falls short of “legalization” or “amnesty.”

Moreover, offering work permits isn’t some further step. It’s part of the deferral process. Once the president officially defers action against some folks (or offers them parole-in-place, which allows them to live in the United States with oversight) they automatically become eligible for work authorization under the Immigration Reform and Control Act of 1986 and driver’s licenses under the Real ID Act of 2005.

This might seem crazy to anti-immigration hawks, but it makes good sense. Letting out-of-status foreigners stay is likely cheaper than deporting them. And if they are going to stay, it is far better to give them the legal means to earn their keep rather than seek handouts on the street or from the government.

Indeed, for over 50 years, every president has used his prosecutorial discretion to let some foreigners stay – and not just a few individuals but entire groups. John F. Kennedy used executive authority to prevent thousands of Cubans from being deported, as did Jimmy Carter and Bill Clinton. George W. Bush used it to temporarily protect illegals stuck in Hurricane Katrina-stricken areas.

Sure, Obama is hinting at going further. But nothing he’s proposing comes close to exceeding the powers Congress has granted him, let alone constituting an “extraordinary abuse of power.”

In fact, notes Stock, he could go even further and offer asylum to the Central American kids lining up at our borders, instead of sending them back as he has been promising to do. Section 207 of the INA gives him the authority to declare a humanitarian emergency and hand refugee status to all of them – and then some. And this wouldn’t be unprecedented, either.

The United States did this as part of Operation Pied Piper to accommodate fleeing children from World War II and then Operation Pedro Pan in the 1960s to provide a safe haven to Cuban kids.

So the real question is why is Obama holding back? It’s possible that he doesn’t fully understand the legal tools he has.

More likely, it’s good, old-fashioned politics. Pretending that he can’t do much till Congress acts offers a convenient way to demonize Republicans with Hispanics. It also prevents a backlash against Senate Democrats in vulnerable red states such as Louisiana in November.

Political cynicism is a bipartisan sport.

SHIKHA DALMIA, a Washington Examiner columnist, is a senior policy analyst at Reason Foundation, a nonprofit think tank advancing free minds and free markets.