Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- Elizabeth Warren isn't running for president!

"I am not running for president in 2020," the Massachusetts Democrat told CNN's Jim Acosta on Sunday.

Done and done. (Crosses Warren off super, duper long list of 2020 Democratic hopefuls.)

Except, well, not. Because in politics -- and especially 2020 politics -- saying "I'm not running" doesn't actually mean you aren't running.

Go back and read Warren's quote. It says "I am not running for president." As in, I am not currently running for president. Not, "I am not and will not run for president." That's a big and important distinction. "I am not eating food right now" is one thing. "I am not eating food and will not eat food" is something entirely different.

Before you attack me as some sort of grammatical nitpicker, remember that all politicians -- except the one currently residing in the White House -- choose their words very carefully. Warren knew she would be asked about 2020 in this interview -- as well as one she did on NBC's "Meet the Press" -- and had a fully-vetted answer at the ready. She did not mistakenly use the present tense and avoid the future tense. Good politicians don't make that mistake.

There's reason for Warren to be cautious of showing her 2020 hand too soon. She is running for a second term in Massachusetts in 2018 and, while she is widely expected to win, voters might not like the idea that Warren has her eye on national office even while she is running to represent Massachusetts again in the Senate.

Her answer to "MTP" host Chuck Todd on Sunday gets at that:

"This government is working better and better and better for a thinner and thinner slice at the top. I am in these fights, and I am in this fight to retain my Senate seat in 2018. That's where I'm focused. That's where I'm going to stay focused. I'm not running for president."

Warren's approach to 2020 vis a vis her 2018 re-election echoes how Hillary Clinton handled a similar timeline in her 2006 Senate race -- a contest dominated by questions about whether she would run in 2008.

Clinton insisted she was focused like a laser on the 2006 race. Of course, she spent $30-plus million on that non-competitive contest as a ramping-up for her 2008 bid, which she announced three weeks into 2007.

Then there's this: Even if a candidate says they won't run for president, there's no penalty for changing your mind later.

"I will serve out my full six year term," then-Sen. Barack Obama, D-Illinois, told NBC's Tim Russert in January 2006. Pressed by Russert whether he would run for president or vice president in 2008, Obama responded: "I will not."

By October 2006, Obama's thinking had changed. "I would say I am still at the point where I have not made a decision to pursue higher office, but it is true that I have thought about it over the last several months," he told Russert.

By January 2007, Obama had formed an exploratory committee to run for president.

The point is this: Warren is being coy. She may not be actively running for president. But, she absolutely has not decided against the race either. She's just trying to ensure she doesn't spent the next eight months answering questions about a race in 2020 when she still has a race to win in November.

It's a smart -- and probably necessary -- strategy. As long as you remember Warren insisting that she isn't running for president means absolutely nothing about whether she actually will do it.