Donald Trump hasn’t exactly kept his plans close to his vest. With another government shutdown deadline looming next week, the president has dismissed the relevance of congressional negotiations and signaled his willingness to pursue a border wall by way of a national-emergency declaration.

It would be, among other things, an aggressively bold move for an administration to grant itself powers, borrow the “power of the purse” from the legislative branch, redirect funds away from other departments, and use American tax dollars to build a border wall in defiance of Congress’ wishes. It’s likely federal courts won’t approve of such a gambit.

But judges won’t be the White House’s only problem. The New York Times reports today that Senate Majority Leader Mitch McConnell (R-Ky.) has “repeatedly warned” Trump that “declaring a national emergency to build his wall would almost certainly spark a rebellion within his party – and a vote to overrule him.”

While several Republican leaders have already denounced the possibility of pursuing a wall through a presidential declaration, Trump still has Sen. Lindsey Graham (R-S.C.) in his corner.

“To every Republican, if you don’t stand behind this president, we’re not going to stand behind you, when it comes to the wall,” Graham said in a speech in Greenville, South Carolina, of the political fight with Democrats over a border barrier. “This is the defining moment of his presidency. It’s not just about a wall, it’s about him being treated different than every other president.” Graham said he doesn’t expect Congress to come up with a deal that would provide money for a wall in spending negotiations to avert another government shutdown after Feb. 15. He said he fears a “war within the Republican Party over the wall.” “This is about more than a barrier. This is about us as a party,” he said.

Oddly enough, in a way, Graham is sort of right – though probably not in the way he intended.

Americans don’t want to spend billions of tax dollars on a border wall. Congress hasn’t approved – and by all appearances, can’t approve – funding for the medieval vanity project. Complicating matters, the evidence of a genuine national emergency along the border simply does not exist.

It’s against this backdrop that Donald Trump, unable to persuade the public, incapable of negotiating a bipartisan deal, and unwilling to offer meaningful concessions to the House Democratic majority, wants to give himself legal powers to address a crisis that only exists in his imagination.

More than a few Republican lawmakers have a problem with this. Lindsey Graham’s message to his GOP brethren is that they should – indeed, they must – go along with the White House’s plan whether they like it or not.

“This is about us as a party,” the South Carolinian argued, and I suppose that’s true. What are Republicans, as a party, prepared to tolerate? How blindly will they follow Trump while he pursues a legally dubious scheme that the American mainstream does not support?

Graham is concerned about a “war within the Republican Party.” Common sense suggests he should therefore counsel his ally in the Oval Office not to divide the GOP over an unpopular and unnecessary idea. Instead, the senator is preparing for that “war” by siding with the president he once dismissed as a crazy “kook” who’s unfit for office.

The South Carolinian is up for re-election next year. If this is Graham’s way of ensuring he doesn’t face a primary challenger, he’s paying an awfully high price.