The US House of Representatives passed a bill today, that would revoke President Barack Obama's executive actions on immigration reform, which protect illegal immigrants from deportation.
The immigration reform reversal was attached as an amendment to a funding bill for the Department of Homeland Security.
The bill now goes to the Senate for a vote there.
However, the Republican Party does not have the super majority of 60 required to pass bills there, and is unlikely to get any supporting votes from members of the Democratic Party.
In any event, the White House has said it will veto the changes to the President's immigration policy.
However, the vote in the House of Representatives can be seen as the GOP's opening shot in the fight over funding the Department of Homeland Security past 27 February.