The partial government shutdown dragged into a 20th day with hundreds of thousands of federal workers off the job or working without pay as the wall fight persisted.
Asked about a national emergency declaration, Trump said as he left the White House for Texas, "I'm not prepared to do that yet, but if I have to I will." He contends such a declaration would allow him to direct the military to begin wall construction.
"So we're either going to have a win, make a compromise -because I think a compromise is a win for everybody- or I will declare a national emergency," he said.
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It's not clear what a compromise might entail. Trump says he won't reopen the government without money for the wall. Democrats say they favor measures to bolster border security but oppose the long, impregnable walling that Trump envisions. He is asking $5.7 billion for wall construction.
Trump's comments came a day after he walked out of a negotiating meeting with congressional leaders - "I said bye-bye," he tweeted soon after - as efforts to end the partial government shutdown fell into deeper disarray. Affected federal workers face lost paychecks on Friday, and more people are touched every day by the rollback of government services.
Putting the standoff in personal terms, the president tweeted before leaving for Texas: "The Opposition Party & the Dems know we must have Strong Border Security, but don't want to give 'Trump' another one of many wins!"
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In McAllen, Texas, Trump will visit a border patrol station for a roundtable discussion on immigration and border security and will get a briefing. But he has expressed his own doubts that his appearance and remarks will change any minds as he seeks money for the wall that has been his signature promise since his presidential campaign.
McAllen is located in the Rio Grande Valley, the busiest part of the border for illegal border crossings.
The White House meeting in the Situation Room ended after just 14 minutes. Democrats said they asked Trump to reopen the government but he told them if he did they wouldn't give him money for the wall. Republicans said Trump posed a direct question to House Speaker Nancy Pelosi: If he opened the government, would she fund the wall? She said no.
Senate Democratic leader Chuck Schumer said Trump slammed his hand on the table. But Trump, who handed out candy at the start of the meeting, disputed that characterization. He said he "didn't smash the table" but "should have."
One result was certain: The shutdown plunged into new territory with no endgame in sight. The Democrats see the idea of the long wall as ineffective and even immoral. Trump sees it as an absolute necessity to stop what he calls a crisis of illegal immigration, drug-smuggling and human trafficking at the border.
Trump also went to Capitol Hill Wednesday, seeking to soothe jittery Republican lawmakers. He left a Republican lunch boasting of "a very, very unified party," but GOP senators have been publicly uneasy as the standoff ripples across the lives of Americans and interrupts the economy.
During the lunch, Trump discussed the possibility of a sweeping immigration compromise with Democrats to protect some immigrants from deportation but provided no clear strategy or timeline for resolving the standoff, according to senators in the private session.
GOP unity was tested when the House passed a bipartisan spending bill, 240-188, to reopen one shuttered department, Treasury, to ensure that tax refunds and other financial services continue. Eight Republicans joined Democrats in voting, defying the plea to stick with the White House.
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There was growing concern about the toll the shutdown is taking on everyday Americans, including disruptions in payments to farmers and trouble for home buyers who are seeking government-backed mortgage loans - "serious stuff," according to Sen. John Thune of South Dakota, the No. 2 Senate Republican.
Some Republicans were concerned about Trump's talk of declaring a national emergency at the border, seeing that as unprecedented interference with the right of Congress to allocate funding except in the most dire circumstances.
"I prefer that we get this resolved the old-fashioned way," Thune said.
Democrats said before the White House meeting that they would ask Trump to accept an earlier bipartisan bill that had money for border security but not the wall. Pelosi warned that the effects of hundreds of thousands of lost paychecks would begin to have an impact across the economy.
"The president could end the Trump shutdown and re-open the government today, and he should," Pelosi said.
Tuesday night, speaking to the nation from the Oval Office for the first time, Trump argued that the wall was needed to resolve a security and humanitarian "crisis." He blamed illegal immigration for what he said was a scourge of drugs and violence in the U.S. and asked: "How much more American blood must we shed before Congress does its job?"
Democrats in response accused Trump appealing to "fear, not facts" and manufacturing a border crisis for political gain.
In an off-the-record lunch with television anchors ahead of his speech, Trump suggested his aides had pushed him to give the address and travel to the border and that he personally did not believe either would make a difference, according to two people familiar with the meeting. But one person said it was unclear whether Trump was serious or joking. The people familiar with the meeting insisted on anonymity because they were not authorized to discuss the meeting publicly.