Donald Trump speaks during a rally in Biloxi, Mississippi on Saturday.AP Photo/Rogelio V. Solis

Already in this young year, Re­pub­lic­an pres­id­en­tial can­did­ates have de­cried Pres­id­ent Obama’s use of ex­ec­ut­ive power—this time for his plan to uni­lat­er­ally tight­en gun back­ground checks.

But many of the GOP hope­fuls have also made clear they would be will­ing to wield the pres­id­en­tial pen them­selves if elec­ted—wheth­er to go around Con­gress and make new policy, or simply to roll back the Obama ac­tions they most des­pise.

This weekend, New Jersey Gov. Chris Christie said on Fox that the president is behaving like “a petulant child” who wants to act like a “king” or “dictator,” before charging that the expected actions were illegal. At a Mississippi rally, Donald Trump said, “There’s an assault on the Second Amendment.” And Sen. Marco Rubio told a New Hampshire crowd that Obama has “waged war on the Constitution.” They all pledged to reverse the expected move—Rubio on Day One and Trump “so fast”—through executive action.

The fight over the nation’s gun laws is just the latest example in a series of battles over Obama’s use of his pen and phone. For a year, Republican candidates have promised to roll back the past seven years—Congress be damned—particularly in the realms of immigration, foreign affairs, and environmental policy.

Perhaps the most severe example of how a Republican candidate would attempt to stretch the powers of the Oval Office is Donald Trump on the issue of immigration. Over the objections of new House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell, Trump says he would temporarily bar all Muslims from the country. While many legal experts call the act blatantly unconstitutional, others, such as the University of Chicago Law School’s Eric Posner, have argued that he wouldn’t need to ask Congress to block noncitizen Muslims. Another of Trump’s extraordinarily controversial pledges, to deport the approximately 11 million immigrants who have illegally come to the U.S, would fundamentally change the fabric of American society.

"Does he understand how his police state would affect the country?” asked Michael R. Strain, a resident scholar at the American Enterprise Institute, in The Washington Post in November. "Apart from the obvious ways that have been much discussed—breaking up families; a massive disruption for businesses, schools, churches, communities; potentially turning neighbor against neighbor—Trump’s powerful Department of Homeland Security would almost surely end up mistakenly apprehending and detaining U.S. citizens. And probably deporting some of them, too."

While the GOP field has roundly sidestepped or denounced Trump’s Muslim ban, other candidates have called for reversing Obama’s executive action allowing more than 4 million immigrants who came to the country illegally live in the U.S. without fear of deportation. As Obama attempts to save his immigration overhaul in the courts, candidates such as Sen. Ted Cruz have said the president has “abused his executive authority and refused to enforce the immigration laws that are currently on the books.

“I will end the lawlessness with the stroke of a pen,” adds Cruz on his campaign website, promising to “use every ounce of my constitutional authority and executive discretion to ensure [the Homeland Security Department] enforces the law instead of violating it.”

The GOP candidates also hope to revert to a pre-Obama environmental agenda, as all of them are skeptical of the scientific evidence behind the human causation of climate change. Cruz, Rubio, and Jeb Bush want to scuttle Obama’s regulatory mandates to cut carbon emissions from power plants and reverse his rejection of the Keystone pipeline. And recently Cruz said that he would pull out of the nonbinding, landmark climate agreement struck last month in Paris, a deal which Rubio also ripped as “ridiculous.”

Not only are top GOP candidates calling to rebuff Obama’s actions in the states, they’re also looking to change them around the world. Rubio wants to reverse the administration’s historic move opening diplomatic relations with Cuba. Trump would like to designate China a currency manipulator and bring back waterboarding as an detainee-interrogation tool. And Cruz would move the U.S. embassy in Israel from Tel Aviv to Jerusalem.

Some changes would be faster than others. On Day One, Cruz and Rubio have said they would tear apart the landmark nuclear agreement signed by Iran, the U.S., Germany, France, Great Britain, Russia, and China, which would limit Iran’s nuclear program for over a decade. Rubio said he would impose sanctions on Iran that day, while other candidates, including Bush, have pushed for first evaluating the effects of the deal, which was struck in July.

“Maybe you ought to check in with your allies first,” Bush said then. “Maybe you ought to appoint a secretary of State, maybe a secretary of Defense. You might want to have your team in place before you take an act like that."

Of course, the Democratic candidates would be willing to push their agenda through executive action too. Karl Rove recently wrote in The Wall Street Journal that Hillary Clinton would lead America in the direction of “banana republics,” tightening gun-show and Internet loopholes, forcing federal government contractors and publicly traded companies to publicly disclose some political spending, preventing deportation of the young immigrant Dreamers, and working to prevent American companies from moving abroad to take advantage of lower corporate tax rates.

Both Clinton and Sen. Bernie Sanders, her chief Democratic rival, approve of Obama’s planned moves on gun control.

Much of Obama’s legacy will be at the mercy of his successor. Even Obama’s choice to change Mount McKinley’s name back to Denali has been knocked by the GOP as executive overreach; Cruz at the time said it was the “latest manifestation of the megalomaniacal, imperial presidency.”

In early September, Trump said that there’s congressional gridlock because there’s “no leadership at the top” and lamented that “signing executive orders is not the way our country was supposed to be run.”

Perhaps buoyed by his steady position atop national polls, Trump now seems even more eager to wield the executive branch’s far-reaching powers over Congress. In mid-December, he told a South Carolina crowd, “The one good thing about an executive action is that the new president can go in—you don’t have to go through a Congress—you can just … go and sign and it’s over.

“It can be unsigned so quickly by the new president, I think probably within the first hour," Trump added. "It could be within about two minutes after I take an oath, assuming I’m lucky enough.”

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