"This may turn out to be a Selma-like moment," said Rep. Sander Levin (D-Mich.) on the House floor just before midnight Eastern time.
It's impossible to judge Levin's claim with the events of Wednesday night/Thursday morning so fresh. But here's what I think I know about the immediate effects of the sit-in.
First, what it will change:
* The Democratic base will be energized beyond belief
The organic nature of the sit-in -- most Democratic members besides Reps. John Lewis (Ga.) and Katherine Clark (Mass.) were unaware of it before it launched Wednesday afternoon -- is just the sort of thing that will thrill rank-and-file Democrats. The Democratic Party committees will fundraise like crazy off this event. So will Hillary Clinton, who will highlight it the next time she speaks publicly. Democrats had been privately concerned about the enthusiasm of their party base when compared to Republicans during the primary voting process. A high-profile event like this one should help narrow that gap.
* Democratic elected officials will see it as way to get their voices heard
Being in the minority in the House is a miserable existence. Unlike in the Senate, there is no filibuster. The minority has to just grin and bear it while the majority rules. The sit-in is a tool that has been used only sparingly in the House (this is just the third time since the 1970s). Given the success of this one -- and make no mistake, this move has succeeded beyond Democrats' wildest dreams -- there will be many within the Democratic caucus who see this as their single most effective weapon in the fight against Republicans. It is far from clear whether a night like this can be replicated. It is almost certain that members will want to try.
* Partisanship in the House will get worse
The spectacle of members shouting down the speaker of the House -- as Democrats did Wednesday night -- isn't going to be forgotten anytime soon by either Speaker Paul Ryan (R-Wis.) or the Republican majority. Ron Brownstein of the L.A. Times said early Thursday on CNN that "all the guardrails" in terms of how House members treat one another will now be gone. He's right.
* John Lewis will be the new hot thing in Washington
Lewis has long enjoyed legendary status with both sides of the aisle in the House due to his prominent role in the civil rights movement. As the sit-in wore on, Lewis rapidly became the face, voice and backbone of the sit-in effort. Expect lots of reposted profiles of Lewis, a man whose place in history is already very much sealed, over the next few days.
* Periscope will be the other new hot thing in Washington
* Republicans will not budge on guns
Democratic Rep. Steve Israel (N.Y.), a former head of the party's campaign arm, said early Thursday that GOP members would go back to their home districts for the July 4 recess and have to explain to their constituents why they wouldn't hold any gun votes.
Israel knows better. The reality is that in 90 percent of the districts House Republicans represent, there is zero desire from their base to act on guns -- and certainly not to do so in response to a Democratic uprising on the floor.
The vast majority of House Republicans not only won't pay a political price for their unwillingness to hold a vote — the move is likely to boost their image among many of their constituents.