President Obama wants his signature climate change regulation to be a hallmark of his White House legacy. But whether the rule, which will be finalized Monday, will remain intact won't be decided until after his presidency as Republicans and the energy industry try to kill it through legislation and the courts.

For now, the emissions rules for power plants that Obama will announce at a Rose Garden ceremony Monday afternoon represents a high point for his presidency's environmental credentials.

Environmental allies, who challenged Obama early in his presidency to act on the climate after a sweeping cap-and-trade bill collapsed in the Senate, quickly praised the effort, though some contended the regulation didn't go far enough considering the United States has met nearly half the final rule's goal of slashing electricity emissions nationwide 32 percent below 2005 levels by 2030. The rest of the roughly 17 percent of emissions the U.S. power sector must cut to meet the mark will be met largely by imposing limits that will shift the power sector away from coal, which provides about 39 percent of the nation's electricity, and toward renewable energy and natural gas.

"It's a simple idea that will change the world: Cut carbon pollution today so our kids won't inherit climate chaos tomorrow. That's what this historic plan will achieve," said Rhea Suh, president of the Natural Resources Defense Council.

Obama will try to use the rule to achieve one of his most ambitious foreign policy aims: Securing a long-desired international climate change agreement, which countries hope will put the world on a path to keep global temperatures from rising 2 degrees Celsius above preindustrial levels by 2100.

But along the way the administration will have to fight off Republicans, who have sought to undermine international confidence in the rule.

Republicans have suggested the idea of sending a letter to the United Nations regarding climate negotiations that are set to begin in November in Paris. It would resemble Sen. Tom Cotton's, R-Ark., missive to Iran, which said Republicans don't support the nuclear agreement that Obama and other world leaders were crafting. Red states, following a call from Senate Majority Leader Mitch McConnell, R-Ky., are considering not submitting plans to comply with the EPA rule because they think all or parts of it are illegal.

Republican presidential contenders slammed the rule and said they would scrap it if they win the White House. Wisconsin Gov. Scott Walker, who has hinted his state won't comply with the rule, said that he would "stop the Costly Power Plan," a play on the rule's name, the Clean Power Plan.

While international negotiators have expressed concern about the Republican resistance, administration officials say diplomats are convinced that the White House is committed to the effort.

After years of the U.S. being a somewhat reluctant participant in the UN negotiations, Obama has vowed to take the lead. Administration officials have told other nations that the U.S. is serious about the talks, with the climate rule serving as the bulwark of the Obama administration's commitment.

"This rule actually enhances in important ways our ability to achieve the international commitments that we have made," Brian Deese, an adviser to Obama, said during a Sunday conference call with reporters.

With the rule now finalized, GOP efforts aimed at weakening the rule are likely to build. They will want to leave a paper trail of disapproval for the rule, which they say will raise electricity costs and kill the coal industry.

Once the rule is submitted to the Federal Register, a GOP Senate source told the Washington Examiner that Senate Republicans are likely to move on a Congressional Review Act, a maneuver that allows Congress to vote down major regulations by majority vote. All 56 Senate Republicans would likely show disapproval of the rule, but centrist Democrats who oppose the rule aren't expected to cross Obama on a Congressional Review Act vote, so it's not likely to survive a veto.

Instead, Senate GOP leadership likely will have to introduce legislation that replaces the power plant rule with an alternative that centrist Democrats might support. Sen. Shelley Moore Capito, R-W.Va., has her bill to roll back the power plant rule waiting in the hopper, which the Senate Environment and Public Works Committee is scheduled to take up on Wednesday. The House, meanwhile, already has passed legislation from Rep. Ed Whitfield, R-Ky., that would handcuff the rule, and Republicans also plan to use the budget process to limit the rule.

Even if those efforts don't clear Congress, the industry and Republicans think they will have cooled the international community's confidence that the U.S. can deliver on the international promises it has made to curb nationwide emissions 26 percent below 2005 levels by 2025, a figure that hinges on the yet-uncertain fate of the power plant rule. Most climate scientists say that greenhouse gas emissions, mainly from burning fossil fuels such as coal, are driving manmade climate change.

"[W]hen 245 house members and 56 senators vote against a rule, even the UN dimwits are going to surmise that all is not well," said Mike McKenna, a GOP strategist who lobbies for energy companies.

Coal-heavy states and the energy industry are expected to file lawsuits, and it's unlikely that they will wrap up in time for the Obama administration to defend it if the rule lands in the Supreme Court. Roger Martella, a partner in the environmental practice at Sidley Austin LLP, suggested that Obama would want a bit more clarity regarding the rule's judicial status heading into the UN talks.

"He's going to want to talk about a rule that's been finalized," Martella said at a Washington event last month. "So there is a question of how soon will the courts look at this."

EPA Administrator Gina McCarthy didn't answer a question Sunday about whether the administration would seek an expedited judicial review in the event of a lawsuit.

Some industry officials who oppose the rule have suggested that the administration would delay publishing the rule in the Federal Register — which is when affected parties can officially file lawsuits and Congress can move to a Congressional Review Act — until December to avoid a potential injunction or a vote expressing widespread disapproval of the rule heading into the UN talks. They contend there is precedent for the EPA to delay publishing controversial regulations. For example, more than three months passed before EPA submitted its proposed rule for carbon emissions limits on new power plants after announcing it in September 2013.

McCarthy, when asked when the EPA would publish the rule in the Federal Register, said, "I can't give you an exact date." An EPA spokeswoman told the Examiner that the agency "will follow our normal procedures for publishing in the Federal Register, which is as soon as practicable."

Still, some see the theory that the EPA would wait several months to submit the rule in the Federal Register as "implausible," said William Yeatman, a senior fellow with the conservative Competitive Enterprise Institute.

"It would be too cynical, even for this administration, to try to advance its foreign policy via publication tricks in the Federal Register. Also, I think they're very satisfied, even proud, of this rule, and also (mistakenly) confident about its politics," he wrote in an email to the Examiner.