KYIV, Ukraine (AP) - U.S. President Joe Biden's decision to end his campaign for reelection brings a new element of uncertainty for Ukraine, which is struggling to fend off Russian advances even as it worries about the future of American support.

No one knows the importance of selecting the right running mate better than Vice President Kamala Harris. With Harris now the leading candidate to succeed President Joe Biden as the presumptive Democratic presidential nominee, a look at the top contenders to be on the ticket.

WASHINGTON (AP) - Biden endorses VP Kamala Harris, throwing Democrats into chaos months before election against Trump.

WASHINGTON (AP) - Preident Joe Biden on Sunday posted a letter to social media announcing that he would no longer seek reelection. The decision by the Democrat came after building pressure from lawmakers, donors, activists and voters within his own party who had concerns about his ability to beat Republican Donald Trump in November’s election.

WASHINGTON (AP) - Sitting in the Oval Office behind the iconic Resolute desk in 2022, an animated President Joe Biden described the challenge of leading a psychologically traumatized nation.

Despite making clear their preference for facing Biden, Trump's campaign has also ramped up its attacks on Harris as pressure on Biden to step down has intensified in recent weeks.

Senate Majority Leader Chuck Schumer, D-N.Y., said in a statement that Biden "has not only been a great president and a great legislative leader but he is a truly amazing human being."