Sen. Kirsten Gillibrand (D-N.Y.) is briefed by staff in her office on Capitol Hill on July 16, 2014. (Melina Mara/The Washington Post)

This tweet has gotten 85,000 retweets and likes in the past 27 hours.

Remember that in 2020, indeed.

Sen. Kirsten Gillibrand's (D-N.Y.) name has come up as a potential Democratic presidential candidate before, of course — pretty much ever since she was appointed to replace that other female senator from New York who ran for president. Our own Chris Cillizza has put Gillibrand on his shortlist of leading 2020 Democratic candidates, and The Post's Paul Kane, who covers her in the Senate, concurs.

Since that tweet, she broke her streak — voting for Nikki Haley to become U.S. ambassador to the United Nations later Tuesday — but it is conspicuous that this former moderate congresswoman turned more-liberal senator has been so anti-Trump on the first few votes of the Trump era. She has now voted against three of four Trump Cabinet-level nominees, which is still more than any other Democrat.

It's hard to say whether that's really a function of angling for 2020 or something else. A big reason she has the most votes against Trump is that she was the only senator to vote against retired Gen. James Mattis for defense secretary. But her publicly stated objections weren't about partisan politics; it was her objection to the idea of a military leader heading up the department before the required seven-year waiting period had elapsed. This required a waiver from the Senate. Gillibrand also voted against that, along with 16 other Democrats.

But none of those other 16 voted against Mattis in the final vote, and Gillibrand did ask for a roll-call vote — giving herself a chance to put her lonely opposition on the record.

It's also worth noting that other potential 2020 Democratic candidates have been voting against Trump's nominees, too. Sens. Cory Booker (N.J.) and Elizabeth Warren (Mass.) both voted against Homeland Security Secretary John F. Kelly and CIA Director Mike Pompeo — in addition to voting against the Mattis waiver. Sen. Bernie Sanders (I-Vt.), who has left open the possibility of a 2020 bid even though he's in his mid-70s, voted against Pompeo, Haley and the Mattis waiver. So through five Cabinet-level votes, Gillibrand was a no on four, while Booker, Warren and Sanders voted no on three apiece.

But we're dealing with a very limited sample size this early in Congress. Gillibrand also has a 2018 reelection campaign to think about — something her office pointed to when asked about this speculation.

Gillibrand spokesman Marc Brumer said, “The only race she is interested in is her reelection to the Senate in 2018, and the only thing she takes into consideration when deciding how to vote on Cabinet nominees is their record and qualifications.”

And Gillibrand, while first joining Congress as a kind of middle-of-the-road Democrat, has been a pretty liberal senator from her earliest days. So these votes shouldn't be hugely surprising.

But they will be interesting to watch going forward. Democrats hate Trump in much the same way Republicans hated President Obama, and as there was a premium on anti-Obama purity for Republicans in 2012, there will be a premium on anti-Trump purity for Democrats in 2020. Every vote that could be construed as being supportive of Trump will be one that could be used against you in the Democratic primary, and Gillibrand and her fellow aspirants know that.

It's certainly worth keeping an eye on — even if we can't tell a ton from five votes.