The Trump administration this week cheered a new House bill to spend $5 billion on a Southern border wall, but its passage is highly unlikely because Senate Republicans are already prepared to cut that number by more than two-thirds.

The fiscal year 2019 House Homeland Security Appropriations spending bill would give a major boost to border wall funding. Beyond the billions of dollars in funding for 200 miles of "new physical barrier construction" along the U.S.-Mexico border, it would also provide funding for improvements aimed at achieving “100 percent scanning” of the border within five years.

The measure will soon move to the House floor, where it can pass with an all-GOP vote and without any Democratic support.

But in the Senate, where ten Democrats are needed to pass legislation, it will be much harder to get significantly more border wall funding than the $1.6 billion requested by the Trump administration.

The Senate Appropriations Committee approved a Homeland Security spending measure in June that includes the $1.6 billion for border wall funding. And Senate Republicans told the Washington Examiner that they plan to stick with the White House’s original request, which is based on the length of fencing or wall construction they can complete in a fiscal year.

“This is what the White House asked for,” said Rep. James Lankford, R-Okla. “There is no reason to put in more than what they asked for and what they need and what they can get done in a year.”

Republicans also know they probably can’t get enough Democrats to approve more wall funding unless they reopen the immigration reform debate, which stalled in the Senate this year.

[Previous coverage: Trump readies full-court press on border wall funding]

Democrats want a pathway to citizenship for at least 1.8 million Dreamers before they can agree to new border wall funding that exceeds the $1.6 billion.

“I have supported significant border security funding as part of a package that provides a pathway to citizenship for Dreamers,” Rep. Chris Coons, D-Del., told the Washington Examiner. “But just a freestanding $5 billion for a border wall, that is not something I would support.”

Sen. John Cornyn, R-Texas, who is the majority whip, pointed out that Senate Minority Leader Chuck Schumer, D-N.Y., at one time was ready to offer $25 billion in border security funding in exchange for a pathway to citizenship for Dreamers.

But Schumer has since withdrawn that offer, which at the time was rejected by Republicans and President Trump, who wanted additional immigration reforms included, such as a new limitation on chain migration.

While the chances seem slim that House Republicans could win their battle to secure $5 billion, Cornyn said there's a chance that wall funding could end up as a bargaining chip in an end-of-year spending deal that wraps together the leftover appropriations measures.

“This has just become a partisan point of contention,” Cornyn said. “I keep hoping somehow we’ll get a breakthrough. It’s going to have to be resolved one way or another."