Washington (CNN) - President Donald Trump has been working the phones ahead of a free-wheeling Senate debate on immigration, the issue that shaped his 2016 presidential campaign.
Trump spoke Monday with conservative allies Tom Cotton of Arkansas and Sen. David Perdue of Georgia, according to sources familiar with the conversations.
The senators have sponsored an amendment that closely resembled Trump's own framework includes $25 billion in border security as well as overhauls of the country's legal immigration program.
The proposal isn't expected to garner 60 votes, the magic number needed in the Senate to pass an amendment. But ahead of what is expected to be a frantic few days on immigration, Trump's outreach reveals the President's center of gravity is still very much with the right flank of the GOP as the debate unfold.
RELATED: Success for Harvard medical students in DACA could mean their parents are deported
Trump's role in the upcoming Senate debate is still uncertain. Democrats believe Trump's made the process more difficult with his rhetoric and constant shifting positions. They argue their Republican colleagues have been under pressure and reluctant to engage in part because they aren't sure where Trump will ultimately land.
"Nailing the President down has been next to impossible, and even when we have an agreement with him it lasts only for hours before he throws it out and starts again," Senate Minority Whip Dick Durbin, D-Illinois, said.
Sen. Jeff Flake, a Republican from Arizona who had been a more moderate voice in the immigration debate, said Trump's been a wild card in the debate, but that he still is holding out hope that Trump will be more willing to strike a compromise than he's let on at times in the past.
"I've said consistently that I think his instincts are better than the advice he gets and every time he speaks, extemporaneously he seems to be in a deal making mode," Flake said. "Sometimes he gets pulled back."
In evidence of Trump's ongoing influence, however, Flake was planning to introduce his own proposal to the debate that closely hewed to what the President has proposed, scaled back only slightly.
© 2018 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved.