Senate members of  President Trump’s own party are poised to stand up to him and force him to use his veto power for the first time.

“After more than two years of keeping his veto pen capped, Trump is going to have to put it to use — twice — courtesy of Republicans,” reports Politco. “In a remarkable bit of timing, the Senate will hold two votes this week placing GOP senators at odds with the president on foreign and domestic policy, likely forcing the first vetoes of his presidency.”

Enough Republicans appear ready to join with Democratic senators in voting to block Trump’s anti-migrant national emergency declaration on the southern border, and to cut U.S. military involvement in Yemen’s brutal civil war.

Trump was warned of the impending votes last night by three GOP senators — Ted Cruz of Texas, Lindsey Graham of South Carolina and Ben Sasse of Nebraska — who “unexpectedly arrived as Trump was having dinner in the [White House] residence with family,” reports the Washington Post.

In a tweet early Thursday, Trump said there will be “A big National Emergency vote today … on Border Security & the Wall (which is already under major construction.” He added, “I am prepared to veto, if necessary.” He called the U.S.-Mexico border “a National Security and Humanitarian Nightmare.”

Last month, after Congress balked on funding his border wall, Trump did an end-run by declaring the national emergency. That raised a major Constitutional issue: Congress’s power of the purse.

“It’s ‘extraordinary’ to see Congress working to claw back power from the executive branch in a matter of days,” said Sen. Rand Paul (R-KY), who Politico says “will vote with Democrats and a handful of Republicans to form a bipartisan majority to try to handcuff Trump on both issues.”

“Congress should declare war and Congress should spend the money. I mean, those are two bedrock constitutional principles,” Paul said. “It has nothing to do with the president, it has to do with the Constitution.”

Last night’s unusual White House visit by the three senators, the Post said, was an “attempted last-minute intervention [that] underscores concerns of senators like Cruz who have voiced serious reservations about the constitutionality of Trump’s declaration but don’t want to cross him on a key vote on border security.”

At least seven Republicans have publicly committed “to join Senate Democrats in supporting the House-passed resolution of disapproval,” reports the New York Times, even as Mr. Trump tweeted that such a vote would be “a vote for Nancy Pelosi, Crime, and the Open Border Democrats!”

Not enough Republican senators appear willing to oppose the president to override a veto.

But, says the Post, “the Senate vote would still stand as an embarrassing rebuff of a key Trump initiative at the hands of his own party. And it would come a day after a Senate vote to end U.S. support for the Saudi-led war in Yemen, marking unusual twin rebukes from a Senate that has mostly bowed to Trump’s wishes.”

Politico says some Trump allies “believe a potential defeat in the Senate over the national emergency declaration is unlikely to cause lasting political damage to the president.”

But, it says, “For Democrats who have seen no similar pushback from the GOP other than a handful of failed judicial nominations and the 2017 collapse of Obamacare repeal there was some hope of a broader shift.”

In a wry comment, Sen. Chris Murphy (D-CT) said that “Maybe Republicans did notice the 2018 election.” He added that scheduling the Emergency and Yemen votes so closely together suggests “Republicans want to peel two Band-Aids off at once.”