After failing to win the Republican nomination for president, Marco Rubio is now going back on his promise to not run for reelection to the Senate.

“Marco Rubio abandoned his constituents, and now he’s treating them like a consolation prize,” said Democratic congressman Patrick Murphy, who is running to replace Rubio.

What’s worse, Rubio is using Donald Trump’s “worrisome” candidacy, which he has supported in various forms in recent months, as an excuse for his change of heart, citing concern over Trump’s racist, sexist, and xenophobic remarks, as well as his still unknown views on other important issues.

“As we begin the next chapter in the history of our nation, there’s another role for the Senate that could end up being its most important in the years to come: The Constitutional power to act as a check and balance on the excesses of a president,” he said in a statement Wednesday announcing his bid to keep his seat.

“If he is elected, we will need Senators willing to encourage him in the right direction, and if necessary, stand up to him,”

That’s right. Rubio spent months after dropping out of the presidential election failing to rebuke Trump in any forceful way, but now plans to make Trump a central part of his campaign platform.

Although Rubio did not mention the Orlando tragedy in the statement, he previously cited it as a reason for reconsidering his decision to not run. It’s unclear what actions Rubio will pursue to prevent further massacres once in the Senate — on Monday, he voted against four gun control bills, two each from Republican and Democratic sponsors.

Rubio also happens to have one of the worst attendance records in the Senate, something Trump pointed out frequently during the Republican primaries, before Rubio dropped out and Trump encouraged him to seek reelection.

Rubio had previously pledged to support his friend, Florida’s Lieutenant Governor Carlos Lopez Cantera, in the race to replace him. Cantera scratched plans to run for Rubio’s seat after Rubio’s announcement on Wednesday.

Congressmen Ron DeSantis and David Jolly also dropped plans to reach the Senate and opened the way for Rubio.

Photo: Marco Rubio parts the curtains to view the crowd before being introduced during a campaign event in Reno, Nevada February 22, 2016. REUTERS/Chris Keane