(Bloomberg) -- Most congressional Republicans remained lined up behind President Donald Trump in his fight to fund a border wall, but some cracks in that solidarity were emerging Tuesday among GOP lawmakers who represent competitive states and districts as the impact of the government shutdown began to spread.

Before an Oval Office address by Trump and with the partial shutdown in its 18th day, the president’s allies insisted they’ll reject any new attempts by Democrats to pass government funding bills without the $5.7 billion the president is demanding for a wall on the U.S.-Mexico border.

“Quite frankly, I see no wavering,” said Representative Mark Meadows, a Trump ally who leads the conservative Freedom Caucus.

The North Carolina Republican said he’d be “surprised” if as many 15 Republicans vote with Democrats on four separate bills being considered this week to fund parts of the government. He said only the roughly half-dozen “usual suspects” in his party would go along. Seven Republicans voted for one of the Democratic funding bills last week.

Reservations

Although Democrats control the House and will be able to pass the measures, they once again will be blocked in the GOP-controlled Senate. Roy Blunt, a member of the Senate GOP leadership, said Republicans in that chamber aren’t feeling any pressure to take up the House legislation to fund the government.

However, a few senators have expressed reservations about the extended shutdown.

Shelley Moore Capito of West Virginia, who heads the Homeland Security appropriations subcommittee, said she might be able to support a stopgap bill for homeland security spending along with reopening the rest of government. She dismissed Trump’s bravado last week about potentially keeping the government shut down for “years.”

“No way,” she said.

Most of the potential Republican defectors are lawmakers who face re-election in 2020 in competitive states or districts. That includes Senator Susan Collins of Maine and Senator Cory Gardner of Colorado — the only two Republicans who will be defending seats in 2020 in states Trump lost — and House Republicans who mostly represent competitive districts.

Breaking Away

Representative Fred Upton a Michigan Republican who voted for the Democratic bills last week, said a group of moderates known as the Tuesday Group will meet to discuss whether to vote for the individual Democrats’ appropriations bills House Speaker Nancy Pelosi plans to bring to the floor this week.

“I will be voting for them,” Upton said, adding that he’ll encourage others to break ranks in the Wednesday meeting.

Brian Fitzpatrick, a moderate Republican from Pennsylvania and a former FBI agent, said he knows what it’s like to not receive a paycheck during a government shutdown.

"We can’t have these debates with the government shut down," Fitzpatrick said.

Vice President Mike Pence and other administration officials went to the Capitol Tuesday night to shore up Republican support for Trump’s position. Throughout the day, the White House had been trying to assuage GOP lawmakers and addressing issues that could threaten their broad support for the president.

The administration has been taking actions mitigate some effects by keeping many national parks open despite a lack of staffing and announcing that tax refunds would go out on schedule.

Pence told them food stamps would continue to be distributed at least through the end of February. The Agriculture Department said it has authority through a provision in previous stopgap spending bill that allows the government to pay obligations for 30 days.

Representative Glenn Thompson, a Pennsylvania Republican, said he said he was relieved by the news from Pence and others in the meeting that money for food stamps and child nutrition will continue to be distributed at least through February.

“I think the conference remains unified, behind the president,” he said.

While Republican leaders said the party was standing behind the president on his demand for wall money, several key GOP lawmakers were skeptical to the idea of using an emergency declaration to break the deadlock.

Representative Mac Thornberry of Texas, the top Republican on the House Armed Services Committee, said it would “be damaging” for the president to reallocate military funds to constructing a border wall. Texas Republican Senator John Cornyn said the standoff should be solved in a less controversial fashion.

Senate Majority Leader Mitch McConnell of Kentucky backed the president on Tuesday. He said he won’t allow a vote on a government funding bill unless it “can pass the House, earn 60 votes here in the Senate, and get the presidential signature — that’s what it takes to make a law.”

In protest, 44 of 47 Democrats banded together to filibuster a package of Middle East policies later in the afternoon.

©2019 Bloomberg L.P.