Hours before the start of a major immigration debate, Senate Majority Leader Mitch McConnell announced he will back a Trump-inspired immigration reform proposal that would provide a pathway to citizenship for 1.8 million illegal immigrants in exchange for new limits on chain migration and a restructuring of the visa lottery system.

“It’s a fair compromise that addresses the stated priorities of both sides,” McConnell said Monday on the Senate floor.

The plan is similar to a framework sent to Congress by the Trump administration. But rather than ending the the visa lottery system as Trump proposed, the plan announced late Sunday by a group of GOP senators would reallocate the annual 50,000 visa openings to immigrants based on skills, rather than a random lottery.

McConnell said the proposal has “the best chance” of becoming law because it has Trump’s support and likely the backing of House Republicans.

The Senate will vote at 5:30 p.m. Monday to proceed to a debate on immigration that is open-ended. Instead of voting on a specific bill, lawmakers will advance a shell bill and then propose legislation as amendments that will require 60 votes to pass.

The McConnell-backed measure was announced late Sunday by a group of senators including Tom Cotton, R-Ark., and Chuck Grassley, R-Iowa.

The legislation would appropriate $25 billion for border security, including a southern border wall. It would limit chain migration to spouses and minor children.

The bill will compete against a measure introduced by Sens. Jeff Flake, R-Ariz., Lindsey Graham, R-S.C., and Minority Whip Dick Durbin, D-Ill., that would provide a pathway to citizenship for Dreamers, but less than $3 billion for border security and fewer restrictions on chain migration.

President Trump has rejected the proposal, but those who back the measure say bipartisan support makes it the most viable legislation in the Senate.