Sen. Marco Rubio (R-Fla.) repeatedly denied he would run for Senate again in 2016, but on June 22, he reversed course. (Peter Stevenson/The Washington Post)

Sen. Marco Rubio (R-Fla.) officially reversed course Wednesday, announcing that he will run for reelection to the Senate after months of insisting that speculation to that effect was groundless and flat wrong.

"Control of the Senate may very well come down to the race in Florida," Rubio said in a statement Wednesday morning. "That means the future of the Supreme Court will be determined by the Florida Senate seat. It means the future of the disastrous Iran nuclear deal will be determined by the Florida Senate seat. It means the direction of our country’s fiscal and economic policies will be determined by this Senate seat. The stakes for our nation could not be higher."

Rubio's decision is a good thing for Senate Republicans who were very concerned that the field to replace him was decidedly lackluster and that with Donald Trump leading the Republican presidential ticket the seat would be lost. The race now moves toward the GOP although it is still likely to be quite close.

A Rubio insider who spoke to The Fix on Wednesday insisted that "running for reelection is not the obvious move politically," adding that: "It would be much safer for him to leave the Senate now and position himself to run for another office in the future."

Maybe!

But, in my mind, to truly understand Rubio's decision you have to look beyond the Senate and beyond 2016. You have to look at 2020.

Now more than ever in politics (and life) people have short memories and even shorter attention spans. Being out of the national spotlight is the equivalent of political death. And for Rubio, who quite clearly wants to run for president again, he was facing four years (at least) of standing on the sidelines if he didn't run for a second term this November.

The state's governorship is up in 2018 — Rick Scott is term-limited out of the job — but state Agricultural Commissioner Adam Putnam (R) has been setting up a run for that office for much of the last decade. Sen. Bill Nelson (D) is up for reelection in 2018 as well, but that's no easy win against an entrenched incumbent.

So, Rubio was staring down four years of, well, not much. Meanwhile, two other top-tier 2020 GOP candidates — House Speaker Paul D. Ryan of Wisconsin and Sen. Ted Cruz of Texas — would remain in office, serving as either a high-profile check on President Hillary Clinton or an alternate voice to the unorthodox conservatism of President Donald Trump. That was a losing proposition for Rubio — and he knew it.

That's not to say that Rubio isn't taking a risk by running for a second term. He is. Florida is a swing state.  Donald Trump, whose numbers among Hispanics are historically low, is leading the Republican ticket. Democrats have a gifted candidate in Rep. Patrick Murphy. (Murphy faces a primary against Rep. Alan Grayson but should win it.)

And, remember that Rubio has said — lots of times — that he didn't like the Senate and thought it didn't do much of anything.  Two quick quotes to that end:

(1) "We’re not going to fix America with senators and congressmen."

(2) “I don’t know that ‘hate’ is the right word. I’m frustrated.”

Rubio, to his credit, doesn't try to gloss over those past statements. From his announcement:

In politics, admitting you’ve changed your mind is not something most people like to do. But here it goes. I have decided to seek reelection to the United States Senate. I understand my opponents will try to use this decision to score political points against me. Have at it. Because I have never claimed to be perfect, or to have all the answers.

He's right about that. Wealthy Republican businessman Carlos Beruff, who has pledged to stay in the Senate race, slammed Rubio as "Washington's candidate," adding: "Career politicians like Marco Rubio worry more about keeping the job than doing the job, and are constantly looking for their next political promotion."

The calculation Rubio made is that the gamble in re(running) in 2016 was a better one than sitting out two years and running against Nelson or Putnam or waiting four years (or even eight years) to run for president again.

I think he's right. The 2016 Senate race is not an easy one — not even for Rubio, a known commodity in Florida and a gifted natural candidate. When you factor in the negatives Rubio took on in the 2016 presidential race — he got demolished in the state by Trump in the March presidential primary — and the various dismissive things he has said about the Senate, you have an even more complicated race. Add on the fact that Trump is, at a minimum, unpredictable as a top of the ticket nominee, and you see that this race is probably a 50-50 proposition for Rubio.

If he loses, it's likely the end of the line for Rubio. Running for president in 2020 or 2024 as an unsuccessful presidential candidate and Senate candidate in 2016 is not exactly a strong foundation on which to build. But, if Rubio passes on this race, it's uniquely possible that by 2020 the Republican Party has already passed him by.

Better to decide your own fate than have it decided for you.