How Republicans are responding to Trump's government shutdown threat The threat related to the building of the border wall.

 -- Speaking to a crowd of supporters at a rally Tuesday night in Phoenix, President Trump vowed to make good on one of the signature promises of his campaign-- the wall along the Mexican border. He even went as far as to threaten a government shutdown over the issue.

“Now the obstructionist Democrats would like us not to do it, but believe me -- we have to close down our government -- we're building that wall!” he declared.

While some Republicans back the idea of funding and building a wall on the southern U.S. border, there is far from universal support across the party. There has been little indication that Republican leadership would be willing to risk a government shutdowns to get their way, as shutdowns can cost the federal government billions of dollars, and tend to be politically unpopular.

Despite the president’s remarks, House Speaker Paul Ryan Wednesday afternoon said a shutdown is unnecessary.

“I don’t think most people want to see a government shutdown,” Ryan said during a press conference in Oregon today. He added that both he and the president share “very legitimate concerns” about the border and agree on the need for a physical wall, but said that a shutdown is “not in our interest.”

In a written statement Wednesday, Senate Majority Leader Mitch McConnell did not directly address the president’s comments on the border wall, but suggested he does not want to hold basic federal funding hostage over this issue. He wrote that his team was working with the White House to "prevent a government default" and "fund the government.”

Trump’s comments in Phoenix, however, likely emboldened staunch conservatives on the Hill who have held up negotiations over budgets and raising the debt ceiling in the past.

Chairman of the House Freedom Caucus, Rep. Mark Meadows (R-N.C.) has argued repeatedly that the GOP should go to the mat over funding for a border wall, and on Tuesday tweeted, "I applaud @POTUS @realDonaldTrump for his commitment to keeping a promise that was central to his campaign -- securing our southern border." He added, "Congress would do well to join the president by keeping our own commitments and including border wall funding in upcoming spending measures."

If the Freedom Caucus, which consists of conservative and libertarian Republican members, is unwilling to compromise on spending bills, as expected, GOP leadership will likely need to win over some Democrats in order to pass their budget bills or raise the debt ceiling and avoid a shutdown.

Knowing this, Senate Minority Leader Chuck Schumer today warned Republicans and the White House not to draw a line in the sand over the wall.

“If the president pursues this path, against the wishes of both Republicans and Democrats, as well as the majority of the American people, he will be heading towards a government shutdown which nobody will like and which won’t accomplish anything,” he wrote in a statement.

House Democratic Leader Nancy Pelosi echoed Schumer’s criticism of Trump’s willingness to risk government shutdown in order to secure border wall funding.

Trump “will purposefully hurt American communities to force American taxpayers to fund an immoral, ineffective and expensive border wall,” she wrote in a statement. She warned of the large financial costs that come with a shutdown, saying, “The last time Republicans shut down the government, their callous recklessness cost the American economy $24 billion and 120,000 jobs.”

Pelosi signaled that Democrats will push back on Trump’s efforts, adding they “will stand fast against the immoral, ineffective border wall and the rest of Republicans’ unacceptable poison pill riders.”

While Ryan has emerged as a vocal advocate for a wall, his Senate counterpart McConnell has been more tepid about the idea. When asked in March about how much the wall was a priority for him this year, he replied, “I’m in favor of border security. There are some places along the border where that’s probably not the best way to secure the border.” In a press conference in April, McConnell said funding for border security or a wall would be “subject to negotiation with our Democratic colleagues.”

Lawmakers in the last few years have used the threat of a government shutdown as a tricky negotiating tool. Democrats have said they will not work with Republicans on the budget if they feel like they are being backed into a corner with ultimatums.

During an April 23 interview with ABC News’ on “This Week with George Stephanopoulos,” Attorney General Jeff Sessions said that he “can't imagine the Democrats would shut down the government over an objection to building a down payment on a wall that can end the lawlessness.” In the coming months, Democrats will likely say the same line back to their Republican colleagues.