When President Donald Trump said he would declare a national emergency to divert more federal funds toward building a wall on the southern border, House Speaker Nancy Pelosi didn’t mince words.

“A Democrat president can declare emergencies as well,” Pelosi said at her weekly press conference, as news broke that Trump would sign a bipartisan spending deal to keep the government open but also take executive action on the border.

Pelosi is playing to some Republicans’ biggest fears around executive power: that a Democratic president would push through policies on everything from health care to gun control through the White House instead of Congress, should Trump lose the presidency in 2020.

“If the president can declare an emergency on something he has created as an emergency — an illusion that he wants to convey — just think what a president with a different set of values can present to the American people,” Pelosi said. “The precedent that the president is setting here is something that should be met with great unease and dismay by the Republicans.”

"You want to talk about a national emergency? Let's talk about today. The one year anniversary of another manifestation of the epidemic of gun violence in America. That's a national emergency. Why don't you declare that emergency, Mr. President? ... A Democratic president could." pic.twitter.com/NDvhb339aT — Kyle Griffin (@kylegriffin1) February 14, 2019

Republicans have already voiced their concerns. In early January, Sen. Marco Rubio (R-FL) said in an interview on CNBC’s Squawk Box that he and his colleagues are wary of the long-term consequences.

“Tomorrow, the national security emergency might be, you know, climate change, so let’s seize fossil fuel plants or something,” he said. “Maybe it’s an exaggeration, but my point is we’ve got to be very careful about endorsing broad uses of executive power in our republic.”

Even Senate Majority Leader Mitch McConnell, who now says he will support Trump’s declaration on the border, two weeks ago said Congress would work to avoid a national emergency declaration, reportedly privately advising Trump against it.

But McConnell seems to have lost this debate. Instead, Trump is heeding the advice of some of his most ardent allies in Congress, the House conservatives in the Freedom Caucus, who have put aside their own qualms about excessive executive power to get Trump a win on the border wall — a pet project that Congress has repeatedly rejected.

So Trump’s coming national emergency declaration is already giving Democrats ideas.

Rising Democratic stars are putting forward a bold agenda — the Green New Deal, comprehensive campaign finance reform, Medicare-for-all proposals. All those ideas face an uphill battle in Congress, where legislation needs to not only pass the 60-vote filibuster-proof threshold in the Senate but also gain support across a wide range of Democratic ideologies in the House. But if they can just declare a national emergency...

“You want to talk about a national emergency?” Pelosi said. “Let’s talk about today — the one-year anniversary of another manifestation of an epidemic of gun violence in America.”