Sources with direct knowledge tell TMZ ... Biden will not come to the L.A. area until the actors' and writers' strikes are resolved. There's still 15 months left before the election, but with strikes that seem to have no end in sight, it could become problematic.

Biden has a long history of supporting unions, and the Hollywood strikes are no different. He said back in May, "I sincerely hope the writers' strike in Hollywood gets resolved and the writers are given a fair deal they deserve as soon as possible."

Here's how significant L.A. and, California is to Biden's campaign. He raised more money in CA than any other state in 2020 -- $105.5 million -- and that represented 21% of money raised for the campaign.

His spokesperson said earlier this month, "The President believes all workers, including actors, deserve fair pay and benefits," adding, "The President supports workers' right to strike."

L.A. County is a huge part of that equation. In 2020 Biden held 20 virtual fundraisers, some at $25,000 a head. One fundraiser alone raked in $2.7M. Celebs like Cher, Jennifer Garner, Barbra Streisand and Cyndi Lauper hosted some of the events.

Our sources say some very rich folks are already offering their homes for big Biden fundraisers this time around ... again, for $25,000 a pop. But we're told, "Nothing has been scheduled. There are no events planned so far, but they will happen when the strikes are over."

We're told Biden feels it's unseemly to raise this kind of money from the Hollywood community when lots of industry folks are struggling.

An industry source with decades of experience in many areas of Hollywood is convinced ... this strike will be over by the end of the year and probably before. But the clock is starting to tick.