CEDAR RAPIDS, Iowa — John Kerry stressed Joe Biden’s Day-One preparedness and downplayed the former vice president’s fourth-place Iowa standing in recent polls during his first speech in support of Biden’s presidential candidacy.

“Today I am endorsing Joe not because I’ve known him so long, but because I have known him so well,” Kerry, 75, said Friday during a town hall event. The two men worked together for decades when they were both senators and again in the White House when Kerry became secretary of state during President Barack Obama’s second term.