Mark Kelly

Of the top three potential running mates, Mark Kelly has the highest favorability rating overall and is particularly strong with independents. Harris is set to make her announcement Tuesday.

With the announcement that President Biden would no longer run for the Democratic nomination, and his endorsement of Vice President Harris, the focus is on who Harris might choose as her running mate.

In bid for continued Senate majority, Democrat Sen. Mark Kelly wins re-election over Trump-backed Republican candidate Blake Masters.

Pennsylvania, Georgia, Nevada and Arizona come into focus in final days. Plus: where things stand in seven other Senate contests.

Recent events are giving Democrats hope of retaining the 50-50 Senate, which they narrowly control with the vice president casting tie-breaking votes.

Though more Republican-held seats are up for grabs in November, Democratic struggles mean the GOP has improved its likelihood to take control of the Senate. Here are the key contests to watch.

For years, the Democrats have been pushing the state further blue. The former astronaut's swearing-in trims the Republican majority in the Senate to 52-48.

"We do elections well here in Arizona. The system is strong and that's why I have bragged on it so much," said GOP Gov. Doug Ducey. Meanwhile, the state GOP tweeted, "DO NOT CERTIFY A FALSE ELECTION!"

These are the 13 races that will determine control of the Senate in the next Congress. To win control, Democrats would need to net-gain four seats, or three seats plus control of the White House.

Five Republican Senate incumbents are looking increasingly vulnerable, while fundraising reports provide glimpses of Democratic strength.