Senators voted 63-33 to begin formal debate on the $2.7 billion emergency supplemental spending bill, with 11 Republicans joining Democrats in supporting the measure to beef up security at the border and improve agencies' capacity to process, house and repatriate thousands of children fleeing from Central America.
The bill also includes funds to help fight wildfires in the drought-stricken West and aid to Israel to support its Iron Dome missile defense system.
Two Democrats in tough re-election fights, Sens. Kay Hagan of North Carolina and Mary Landrieu of Louisiana, voted against the measure.
Nearly 60,000 unaccompanied children, mostly from Guatemala, El Salvador and Honduras have entered the U.S. this year alone, seeking refuge from intensifying violence and poverty. That figure has doubled since last year, a jump many Republicans have blamed on misinformation over the 2012 Deferred Action for Childhood Arrivals program, which grants some undocumented immigrants relief from deportation.
While most lawmakers agree something must be done to deal with the crisis before Congress departs Thursday for August recess, the parties are sharply divided on how to do so.
In the GOP-controlled House, a proposed $659 million package would give the Obama administration just a fraction of the $3.7 billion it requested, with most of it going toward increased law enforcement.
Most Republicans, and some Democrats, oppose increased funding without changes to a 2008 anti-trafficking law that means children who turn up at the border sometimes stay in the U.S. for years before seeing an immigration judge. While the Senate bill includes no legislative language, the House plan would require unaccompanied children detained at the border to have their deportation hearings within a week.
While House Speaker John Boehner, R-Ohio, expressed optimism that the lower chamber's bill could pass, pressure from Democrats who have called for legislative changes to be dealt with separately, and Republicans who have demanded ramped-up deportations, could make passage a heavy lift. And even if the bill were successful in the House, it would surely fail in the Senate in its current form.
But with less than two legislative days to go before August recess, Senate Majority Leader Harry Reid has floated a plan to attach the comprehensive immigration reform language bill that passed the Senate last year with a bipartisan majority. Doing so, Reid said, would force House leadership's hand on an issue it has been assiduously avoiding.
"Maybe it's an opening for us," Reid told reporters Tuesday. "They are finally sending us something on immigration. Maybe we could do that."