It's not just that Colbert's nightly Trump-bashing, which has propelled his CBS show to the top of the ratings heap, appeals to Democratic viewers looking for someone to topple the president.
It's that Gillibrand was hoping to break through the static of a soon-to-be-crowded 2020 field in the midst of a government shutdown.
Even with the comedian's help, the New York senator's exploratory committee didn't make the front page of her home-state Times.
Now anyone can emerge in such a wide-open field. But how does she hope to distinguish herself?
Gillibrand's opening bit of self-branding took place when she said on the "Late Show" that "as a young mom I am going to fight for other people's kids as hard as I would fight for my own." (Of course, with Elizabeth Warren and Kamala Harris, she won't be the only woman in the race.)
She is "one of the more forceful critics of the Trump administration," as the Times put it, but the paper also noted what's likely to be a major line of attack against her.
As "a former corporate lawyer," she has "been criticized by opponents as a politician without a firm ideological bearing of her own, having transformed from a pro-gun, conservative upstate congresswoman with deep ties to Wall Street financiers to a crusading liberal who rails against guns and refuses corporate political action committee money."
In my view, this isn't likely to hurt her much. Gillibrand once had to reflect the more moderate views of her upstate New York congressional district. When she was appointed to the Senate to replace Hillary Clinton, she became more liberal to match that blue state and has moved further left in preparing for a White House run. Donald Trump, after all, used to be a Democrat.
The Week says her biggest weaknesses are "her close ties to Wall Street, her fondness for the social liberalism of well-off urban hipsters, and her status as a leading representative of the entrenched establishment of her own party."
There are questions about her political agility. In a late October interview, she said she would serve her full six-year term. The press gives pols a pass for these outright lies, but she could have left herself a little wiggle room as she cruised to reelection.
The Clintons, and Hillary in particular, did a great deal for Gillibrand. But she ticked off their loyalists by saying, as she embraced the #Me-Too movement, that in retrospect Bill Clinton should have resigned over the Monica Lewinsky mess.
Gillibrand alienated some liberal donors when she became the first prominent Democrat to call for Al Franken to resign over those groping incidents. But that seems like a bum rap, and the pressure for Franken to quit would have built regardless.
The Washington Post not-so-helpfully notes that her New York colleagues nicknamed her "Tracy Flick" after the bubbly, blond and ambitious character played by Reese Witherspoon in the movie "Election." Men rarely get nicknames for being ambitious.
At this early stage, every new entrant triggers debate over what kind of Democrat could beat Trump. Does it need to be someone who's bombastic or measured? Experienced or newcomer? Hyperpartisan or healing? Does it need to be a woman?
For now, at least, Gillibrand isn't getting much attention for a newly minted candidate. Whether she can change that in the coming months will determine whether she can lift herself out of the second tier.