Bernie Sanders spoke to his supporters for 23 minutes Thursday night. It had all the makings of a drop-out speech — a recitation of all the campaign had accomplished, thanks to everyone who supported him — except that, at the end of it, Sanders didn't end his primary challenge against presumptive Democratic presidential nominee Hillary Clinton.

"We have begun the long and arduous process of transforming America, a fight that will continue tomorrow, next week, next year and into the future," Sanders promised near the end of the speech.

Those words turned behind-the-scenes grumbling from Democrats about why Sanders hadn't dropped out of the race yet into more open concerns that the longer he stays in, the more damage he is doing to Clinton in her challenge to Donald Trump. (Note: There's very little evidence that Sanders is currently damaging Clinton. Democrats in polling released over the past 10 days have largely coalesced behind Clinton and with the prospect of a President Trump as the alternative, it's hard for me to imagine that the vast majority of the party base will not soon line up with the former secretary of state.) It also raised the urgency in many Democratic circles to get Sanders out.

To those grumblers I would say two things: (1) It makes no sense for Sanders to get out of the race right now, and (2) You have no way of getting him out anyway.

Remember that most politicians drop out of races because they run out of money and/or they are looking to their political future and want to make sure they leave a good impression with party leaders. "He ran a good race — and got out when he should have," is the sort of approving sentiment I've had expressed to me myriad times by members of both parties' political establishment over the years about a rising star pol.

Here's the thing with Sanders: He's never been a Democrat before. Yes, he caucuses with Democrats in the Senate. Yes, he ran (and is running) for president as a Democrat. But, Sanders isn't someone who has ever been part of the Democratic party apparatus. He's not someone who is terribly worried about what the party could (or would) do to him if he stays in the presidential race longer than "they" see fit. And, at 74, it's very unlikely Sanders has an eye on 2020 or 2024 to make a repeat run for president.

In short, none of the levers that the party typically pushes to get unwanted candidates out of races works on Sanders. Can you imagine if in a closely divided Senate in 2017, Majority Leader/Minority Leader Chuck Schumer said that Sanders couldn't caucus with Democrats anymore because he didn't endorse Clinton at the right time? No, you can't imagine it because it would literally never happen. Or how about if Schumer stripped Sanders of his committee assignments or even pushed him off one of the marquee committees on which he currently sits? Sanders — and the millions of people who support him — would instantly go bananas. And, because of Sanders's national profile, it would be a huge national story.

Less talked about, but no less important is the fact that the Justice Department is still investigating Clinton's decision to use a private email server to exclusively handle her electronic communication during her time as secretary of state. While the expectation has been for months that an announcement of the investigation's finding was coming within days, no word has come yet.

If you are Sanders — and you know there's not a whole hell of a lot that the Democratic Party can do to actually hurt you — why not stay in the race for a while longer just in case the FBI either indicts Clinton or severely reprimands her? Neither seems likely. (Note: I am not a lawyer!) But, if you have been actively running for president for much of the past 18 months, why would you end your candidacy now with an investigation involving your opponent still ongoing?

Yes, it's possible that if Sanders is seen as overstaying his welcome in the race — and we are just starting to get into that space — the Clinton folks could take away some of his convention goodies or knock down his speaking slot. But, I've always been skeptical that the Clinton people were going to cave to Sanders's demands regarding the party platform, the elimination of superdelegates or the removal of Democratic National Committee chairwoman Debbie Wasserman Schultz anyway.

In terms of long-term problems and punishments, there's very little of consequence Democrats can do to Sanders. He knows it — which is why he's still in the race.