The proposed immigration reform bill faces another procedural vote in the Senate on June 26, 2007.
Today’s action will determine whether the bill is allowed to go forward, possibly toward passage by week’s end.
President Bush is predicting victory, but Republican Conservatives are determined to block the legislation and backers need 60 votes to resurrect it.
Just 45 Senators, including only seven Republicans, supported such a move two weeks ago.
The bill would tighten borders, require workplace verification and create a path to legal status and possible citizenship for roughly 12 million illegal immigrants.
Bush is keeping the pressure on lawmakers, but many Senate Republicans said the bill doesn’t do enough for border security.
They also oppose any policy that suggests illegal immigrants are getting amnesty.