Throughout his presidential campaign, Bernie Sanders staked nearly every one of his politically improbable ideas -- from getting money out of politics to single-payer health care -- on a political revolution that would sweep like-minded supporters into office and force stubborn politicians to change.

But as his presidential campaign winds down, it's still very much an open question of how much that revolution is taking off.

After Tuesday night, Bernie Sanders is 1-for-3 when it comes to major congressional candidates he's endorsed, with three more high-profile races to come. But only one of them would register as a big statement win for Sanders's movement -- and it will be exceedingly tough to win that one.

To the extent we can draw conclusions from individual congressional races, it's this: There doesn't seem to be a Sanders political revolution happening, at least not yet. Sanders's endorsements seem to have come too little, too late in many cases. His one big victor Tuesday -- breakout progressive star Zephyr Teachout winning her primary for a swing seat in New York's Hudson Valley -- had the backing of numerous other progressive groups. Teachout also had the benefit of name ID from an upstart primary campaign against New York Gov. Andrew Cuomo (D) two years ago.

To be sure, the potential is there. Sanders's fundraising skills and star power is unparalleled right now in the progressive community. As my colleagues David Weigel and John Wagner point out, he took in more than $229 million in donations through May, and the vast majority of that came in low-dollar increments -- i.e. grassroots support. His campaign brags he has a donor list of 2.7 million people on it. And when he put out a video earlier this month calling on supporters to run for office, 21,000 pledged they would or would help a Sanders supporter win.

But endorsements are more than just lending your name to a candidate and asking for money, say those who do it for a living. The political arm of the abortion-rights PAC Emily's List, for example, works with candidates they endorse on a daily basis, helps them hire staff and build up their campaigns and tries to mobilize women to vote on election day.

There is, of course, recent precedent for changing a political party by focusing intently on congressional primaries. Look no further than 2010, when the tea party took hold by pushing a few established Republican lawmakers out of office and effectively instilling fear in Republicans who tack to far to the middle. Today there are several, powerful organizations on the right backing primary challengers and more conservative outsiders who might not have had a chance even a decade ago.

Sanders doesn't seem to be doing much beyond sending an email to his donors, though Weigel and Wagner report there's talk in his campaign of setting up a way to do more.

And perhaps that's for good reason. Sanders, after all, has been busy. He had been running a full-fledged presidential campaign. His first major congressional endorsement, Lucy Flores, a former gang member looking to upset Harry Reid and the Democratic establishment in an up-for-grabs race in Nevada, came three months before the election. Flores's fundraising and name recognition got a boost, but it wasn't enough to propel her to victory in a three-way primary.

A similar situation played out in New York's 24th congressional district, another up-for-grabs seat for Democrats. Sanders endorsed college professor Eric Kingson four weeks before Tuesday's primary. Kingson told's Mark Weiner that Sanders's fundraising email lead to some $20,000 in contributions from more than 3,800 people a few hours after it was sent.

But he lost Tuesday's primary to an Emily's List-supported candidate who also had New York's Democratic establishment behind her, Colleen Deacon.

In fact, Sanders's only big win so far in these primary seasons was a candidate that Emily's List and numerous other progressive groups supported. Teachout is a law professor whom some have compared to Elizabeth Warren and many progressives told us was on their list of the next big movement leader. In other words, she was making waves in progressive circles even before Sanders's big presidential campaign; his support was the icing on the cake.

Sanders's other endorsees are up later this summer, but there's only one that could be considered a real test of his revolution.

That comes in Florida, where Sanders essentially declared war on the Democratic establishment by backing the opponent to the Democrat literally in charge of the party, DNC Chair and Rep.Debbie Wasserman Schultz. Challenger Tim Canova is a law professor who has actually been raising money and getting national attention, but to be competitive he's got to capitalize on Sanders's endorsement and overcome a district that isn't terribly friendly to a primary challenger like him.

Sanders's other two endorsees present less of a showdown with the establishment. Sanders has endorsed Pramila Jayapal running for an open congressional seat in the Seattle area. So has Emily's List, Democracy for America and numerous other progressive groups. Jayapal is aiming to be the first Indian American woman elected to Congress and is considered one of the front-runners in a nine-way primary Aug. 2.

He's also endorsed former senator Russ Feingold for his old seat in Wisconsin. Feingold's primary is Aug. 9 and he faces no serious Democratic challenger. In fact, he is the Democrats' chosen candidate to try to unseat Sen. Ron Johnson (R) in November in what's expected to be one of the most competitive races in the country.

Political revolutions take time, caution those who have worked on them. After Howard Dean lost his presidential bid in 2004, his supporters transitioned Dean for America into Democracy for America, and the organization is still a big part of the progressive movement.

"What's interesting to me," said Neil Sroka with Democracy for America, "is not so much the wins and losses that happen this year, but what happens over the next few cycles to the candidates endorsed by Sanders or who are inspired to run for office by Bernie Sanders's campaign."

For now, though, Sanders's political revolution doesn't seem to be taking off at the congressional level.