DETROIT (AP) — President Joe Biden is forcefully defying the growing number of critics in his own party who have called on him to exit the race, pivoting to warnings about a second Donald Trump term and declaring he is “not done yet.” As a raucous Detroit crowd chanted “don’t you quit!” and “we got your back!” Biden said again that he was still running for reelection and vowed to “shine a spotlight” on Trump. The show of force from Biden at the Friday evening rally was part of his team’s relentless sprint to convince fretting lawmakers, nervous donors and a skeptical electorate that at the age of 81, he is still capable of being president.