What's in the $118B U.S. Senate deal to address migrant backlog at southern border?

Senators in Washington, D.C, have come out with a carefully negotiated $118 billion US compromise that pairs tens of billions of dollars in wartime aid for Ukraine with new border laws aimed at shrinking the historic number of people who have come to the U.S. border with Mexico to seek asylum.

The legislation faced immediate opposition from many Republicans in both chambers, and House leaders said it may not even receive a vote, a move that could backfire with voters in an election year. But bipartisan negotiators are labouring to sell the package as part of a last-ditch effort to approve money for Ukraine's defence against Russia, emphasizing that Congress has the best chance in years to make changes to U.S. immigration law.

The bill would also send military aid to Israel, funding for allies in the Asia-Pacific and humanitarian aid for refugees fleeing Gaza.

The package has also drawn strong opposition from Donald Trump, the likely Republican presidential nominee, and his most ardent backers.

"Why would I help Joe Biden improve his dismal 33 per cent [approval rating] when he can fix the border and secure it on his own?" Republican House member Troy Nehls told a reporter last week.

The package contains $60 billion in aid for Ukraine and $14 billion for Israel. In addition, $10 billion would aid humanitarian efforts in Ukraine, Israel, Gaza and other places.

Without the Ukraine aid, Democratic Majority Leader Chuck Schumer said, he believes Russian President Vladimir Putin "could be rolling over Ukraine and even into Eastern Europe."

Republican Senate Minority Leader Mitch McConnell said in a statement that "America's sovereignty is being tested here at home, and our credibility is being tested by emboldened adversaries around the world."

Republicans wanted border security measures attached to any bill that proposed more aid for Ukraine. Here's a look at some of the proposed border changes:

The package would also send $20 billion to immigration enforcement, providing money to hire thousands more officers to evaluate asylum claims, add hundreds of more Border Patrol agents and help stop the flow of fentanyl.

The bill would overhaul the asylum system with tougher standards and faster enforcement.

Asylum offers protection to people fleeing persecution for race, religion, political affiliation or membership in a discriminated group. It is part of international law and helps the U.S. protect human rights, but the system has become overwhelmed in recent years with historic numbers of people seeking asylum at the border with Mexico.

Under the proposal, migrants would have to show during initial screenings that they have a reasonable possibility of being granted asylum. Migrants would also be barred from making an asylum claim if they are found to have a criminal history, resettled in another country or could have found safety if they had resettled in their home country.

Migrants who cross the border illegally between a port of entry would be detained and receive a screening within 10 to 15 days.