Senator Marco Rubio went down the list of political enemies and rivals like a roll-call vote President Obama, Hillary Clinton, both of his possible Democratic rivals, Representatives Patrick Murphy, and Alan Grayson. And even Senator Chuck Schumer, Democrat of New York, whom Mr. Rubio said that he wants to prevent from becoming majority leader.

The name that did not came Mr. Rubio’s lips as he addressed supporters at the opening of a new campaign office, was Carlos Beruff, a wealthy businessman and Mr. Rubio’s lone, long-shot Republican challenger in Florida’s primary on Tuesday. Mr. Beruff’s central campaign theme seemed to be that Mr. Rubio was insufficiently fond of Donald J. Trump.

Mr. Rubio began this year with hopes, of being the face of generational change, in his party on the road to the White House. But he found himself reversing a decision to leave the Senate instead, seeking a second term for a job that he had essentially scorned.

Last year, acting on a Florida Supreme Court ruling that the congressional district map was unconstitutional, the court upheld a new map recommendation that altered 24 of the state’s 27 congressional districts.

What happened in these Florida races could help determine both the fate of the Senate and the political complexion of the House.

Susan MacManus, a state politics expert at the University of South Florida said,“For the first time, every single congressional district is competitive. What haven’t we seen in Florida this year? That’s the question. A lot of people think that this is the place where the Senate is won or lost. Many think that is why Hillary spends so much time here — not so much because she is worried about Florida, but because they desperately want to change that Senate seat.”

By Prakriti Neogi