Story highlights Florida Sen. Marco Rubio will seek re-election for his seat, a complete reversal from his previous position

Rubio is expected to make the announcement Wednesday afternoon

(CNN) Florida Sen. Marco Rubio is seeking re-election to the Senate, publicly admitting he changed his mind and giving a boost for Republicans facing a tough fight to maintain their Senate majority in November.

"I changed my mind," Rubio said frankly in an interview with CNN Wednesday. "I honestly believe that no matter who is elected president we're going to need a Senate full of people willing to act as a check and balance on the excesses of the next president, and I think given the state of this race we're going to have a lot of that over the next few years."

Rubio's announcement marks a 180-degree turn from where he was even just a month ago, when he insisted he would give up his Senate seat at the end of this term. He even used the fact he wasn't running as an excuse for missing a large number of votes during his unsuccessful bid for the Republican presidential nomination.

Speaking with CNN, Rubio defended his voting record, saying he had helped "thousands of people in Florida" though his office.

But he wouldn't commit to serving a full six-year term if re-elected.

Read More