The White House is proposing a $400 weekly federal unemployment benefit as part of its $1.6 trillion stimulus package

• The White House is proposing a $400-a-week federal unemployment benefit as part of its stimulus package.
• It would be retroactive to September 12, Roll Call first reported.
• There appears to be early agreement among lawmakers and the White House that any federal benefit should pick up where a program from the administration left off.
• "I think a lot of it is probably cost, and some of it is trying not to interact with a really weird program we don't fully understand," Michele Evermore, an expert on unemployment, told Business Insider.

The White House is proposing to restore federal unemployment benefits at $400 a week as part of its $1.6 trillion stimulus plan offered to Democrats on Wednesday, Bloomberg reported.

The plan would be retroactive to September 12 and expire on January 1, per Roll Call, which first reported the details of the spending proposal.

That means payouts would be dated just a week after the date when the Federal Emergency Management Agency capped funding for six weeks' worth of $300 payments for states in the Lost Wages Assistance program. President Donald Trump enacted the program in early August through executive order.

There appears to be early agreement among lawmakers and the White House that the federal government should pick up where FEMA left off. Democrats have proposed reviving the $600 federal benefit that expired in the summer through January 31, making it retroactive to September 6.

Read more: Stimulus talks press on as dealmakers push for another boost to unemployment payments. Here's everything you need to know about the rescue package.

Michele Evermore, a senior policy analyst at the National Employment Law Project, said lawmakers were likely trying to avoid technical hurdles that could emerge if payments were retroactive to August, such as a jobless person receiving double the unemployment benefits from overlapping federal programs.

"I think a lot of it is probably cost, and some of it is trying not to interact with a really weird program we don't fully understand," Evermore told Business Insider.

She added that "at this point, even small technical difficulties are a really big deal, since state systems have been through so much."

The White House's unemployment program is still distributing payments in many states, but experts don't know how many people are receiving them, since states aren't required to report those figures, Evermore said.

Congress and Trump in March enacted a $600 federal supplement to state unemployment benefits that many experts have said helped people buy groceries and pay rent and propped up the economy. It lapsed in late July and lawmakers have been fiercely divided on a replacement amount.

Many Republicans have argued that the $600 federal payments discourage people from returning to work, a claim that numerous studies have challenged.

New jobless claims have plateaued in recent weeks, regularly topping 800,000 over six months into the pandemic. About 26.5 million Americans are receiving unemployment benefits, per Labor Department data.

Treasury Secretary Steven Mnuchin said during a Fox Business interview on Wednesday that Trump instructed administration negotiators to increase their spending proposal significantly above $1 trillion. It would include a second round of $1,200 direct payments, he said.

Mnuchin and House Speaker Nancy Pelosi have been negotiating for four days.