House Republicans and Democrats are headed for a showdown this week over the $612 defense authorization bill.
Democratic leadership is lining up against a bill that has been historically passed with bipartisan support, hours before the House takes up the bill on the floor.
Minority Leader Nancy Pelosi (Calif.) will whip members of her party against the bill, according to an aide, and other Democratic leaders joined her in opposing it.
"We heard a presentation directly from the Department of Defense saying that this bill is the wrong bill," Becerra added.
The House Democratic Caucus was briefed on Wednesday by Deputy Defense Secretary Bob Work.
House Armed Services Committee ranking member Adam SmithAdam SmithSenior Dems want nuclear warhead audit Dems warns Trump nuclear push would suck money from budget Treasury chief's global debut will reveal much about his trade stance MORE (D-Wash.) also said he would oppose the bill.
His opposition comes despite the Armed Services Committee passing the bill by a strong bipartisan vote of 60-2, with one Democrat and one Republican in opposition.
Democrats are opposing the $612 billion bill because it would leave spending ceilings in place that were created by the 2011 Budget Control Act, while increasing war funding.
The Republican defense bill would authorize $523 billion in base funding for the Pentagon, and an additional $96 billion in war funding.
President Obama had requested more in base funding and less in war funding: $561 billion and $51 billion.
A Republican staffer said it would be unprecedented for Pelosi to whip against the bill.
"No one is 100 percent in love with it, but they know they get their say. ... Nobody knows what happens if one party just walks away from that process," the aide said.
Becerra acknowledged the bill typically passes with bipartisan support but noted the White House opposes this defense bill.
"It's the wrong way to invest in America's security and to move our country forward," he said.
The bill also contains other provisions that have drawn White House objections, including restrictions on its ability to transfer Guantanamo Bay detainees, a proposal to overhaul the military retirement system, a rejection of base closures, and proposals to retire weapons systems like the A-10 "Warthog" attack jet.
Armed Services Chairman Mac Thornberry (R-Texas) said he believes the bill will still pass, despite Democratic opposition.
"I think we'll still pass it," he said. "It's really unfortunate because it has this tradition and history of bipartisan support in overwhelming numbers.
“We just haven’t seen somebody use it as pawns for some other agenda,” he added.