The Democrat grabbing the most attention right now on the 2020 presidential campaign trail isn’t even running for president.

Hillary Clinton is firmly inserting herself into the campaign – arguing without evidence that Democratic presidential candidate Rep. Tulsi Gabbard of Hawaii is a “Russian asset,” and mocking President Trump’s direct interactions with foreign leaders.

GABBARD SAYS SHE'S OPEN TO FACE-TO-FACE MEETING WITH CLINTON

The former first lady, senator from New York and secretary of state, and the first major-party female presidential nominee, has remained in the spotlight after winning the 2016 national popular vote but losing the election and the White House to Trump. And she’s served as a longtime foil for Republicans.

But her comments and actions in recent days have elevated her relevance in the 2020 campaign to a new level – renewing questions about her role in the race for the White House and sparking some speculation that she still has ambitions to mount a third bid for president.

Her top aides downplay such speculation.

“The short of it is that she’s on a book tour and is feeling unconstrained about speaking her mind,” longtime Clinton spokesman Nick Merrill told Fox News. “It’s easy to over-ascribe a strategy about every word she utters, but it’s as simple as that. She’s out there telling the truth.”

Clinton’s criticism of Gabbard and the candidate’s fierce pushback quickly dominated the 2020 campaign headlines. Many of the other Democratic White House hopefuls were asked to weigh in on the conflict.

Sen. Cory Booker of New Jersey, a top supporter and surrogate for Clinton during the 2016 election, told reporters after a stop in New Hampshire on Monday that “I am disappointed that this has been in the news as long as it’s been. We need to focus on winning this election and that for me, talking about the issues, talking about the urgencies that we have before us and not indulging in what I think is, for me, not a relevant story.”

Booker told reporters throughout the day that “I will not indulge” in weighing in on the controversy or directly reacting to the comments by Clinton or Gabbard.

Gabbard, in a blistering video released over the weekend, suggested that Clinton had “smeared” her as payback for the Hawaii congresswoman’s endorsement of Sen. Bernie Sanders in the marathon 2016 Democratic presidential primary battle. Gabbard quit her role as a vice chair in the Democratic National Committee to back Sanders – a one-time longshot who waged an outsider fight for the nomination that didn’t end until he endorsed the eventual nominee well after the end of the primaries.

"If you stand up to Hillary and the party power brokers -- if you stand up to the rich and powerful elite and the war machine, they will destroy you and discredit your message,” Gabbard said. “But, here is the truth: They will not intimidate us. They will not silence us."

Sanders, who’s running a second straight time for the nomination, took to Twitter on Monday to defend Gabbard, an officer in the Hawaii national guard who served in the war in Iraq.

“Tulsi Gabbard has put her life on the line to defend this country. People can disagree on issues, but it is outrageous for anyone to suggest that Tulsi is a foreign asset,” Sanders wrote.

Fellow Democratic presidential contenders former Rep. Beto O’Rourke of Texas, tech entrepreneur Andrew Yang, and best selling spiritual author Marianne Williamson also defended Gabbard.

In addition to suggesting Gabbard was a "Russian asset" during a podcast last week, Clinton asserted, also without evidence, that Moscow was "grooming her to be the third-party candidate" to serve as a spoiler in helping Trump’s re-election.

While Clinton’s claims are unsubstantiated, Gabbard – who preaches anti-interventionism as she runs for the White House – has been promoted by Russian state-owned media and some alt-right websites.

Gabbard reiterated on Monday to reporters that she’s committed to not running as a third-party candidate and said she would vote for the eventual Democratic standard-bearer.

CLINTON ADMONISHES TRUMP AFTER HE URGES HER TO RUN AGAIN, SAYING 'DON'T TEMPT ME'

The latest episodes – plus Clinton’s back and forth with Trump on Twitter a week ago when the president tempted her to run again and she responded by saying “don’t tempt me” – all spark a conversation of just what her role should be in the 2020 campaign.

There’s no script for just what a former presidential nominee should do and say in ensuing elections. She’s held conversations with some of the candidates, giving her advice. And she’s helped the party raise money, headlining fundraisers for the Democratic National Committee.

For Booker, Clinton’s role is clear.

“She’s an extraordinary statesperson in our party. This is one of the most successful secretary of states easily in my lifetime,” he highlighted. “She needs to play a leadership role in our party going forward and I am looking forward to her doing so.”

But Larry Cohen, one of Sanders' top supporters, warned that Clinton could harm the eventual 2020 nominee by weighing in against specific candidates, even a longshot like Gabbard.

Clinton has "put a lifetime into the Democratic Party. She deserves to be heard," said Cohen, a prominent member of the Democratic National Committee who also chairs Our Revolution, the spinoff of Sanders' last presidential campaign. But "in this senior leader role she has," Cohen said, "it's her job to embrace the range of politics within the party and not polarize within it."

The Associated Press contributed to this report.

