WASHINGTON — Joe Biden’s insistence that he is the Democratic nominee for president and won’t be forced out of the race appears to have stemmed public Democratic defections — at least for now.

While he’s certainly not in the clear and many Democrats are privately and publicly grumbling that he can’t beat Donald Trump this fall, Biden seems to have staunched the bleeding as he and his allies work to shore up support for his beleaguered presidential campaign.

“If the opposition is…