West Virginia Sen. Joe Manchin is considering running as a Democratic challenger to Vice President Kamala Harris, sources close to the senator told CNN. On Sunday, Manchin joined the wave of politicians urging the incumbent President Joe Biden to drop out of the race. Manchin left the Democratic Party in late May citing extremism in both parties and was previously linked to a presidential run as a centrist alternative.With the Democratic National Convention set to begin Aug. 19, several challengers will likely toss their name in the ring for the nomination with delegates still on the table, despite Biden endorsing Harris.