Susan Collins can tell you why not to trust a promise in Washington

Take Maine Republican Sen. Susan Collins, who got seemingly ironclad promises in order to sign her crucial vote onto the GOP's tax reform bill (a banner achievement, but the Republicans' only real legislative accomplishment while controlling Congress and the White House). The tax bill also repealed the individual mandate -- the Obamacare requirement that Americans have health insurance or a pay a fine or tax.

One of the things Collins got in exchange for her vote, she said at the time, was the assurance of the Senate Majority Leader Mitch McConnell that he would allow a vote on her plan along with Florida Democratic Sen. Bill Nelson to give insurance companies money to help pay for the most expensive patients. Separately, there was to be a vote on a plan by Sens. Lamar Alexander, a Tennessee Republican, and Patty Murray, a Washington Democrat, to temporarily shield insurance companies from President Donald Trump's unilateral decision to end Obamacare cost-sharing subsidies that helped them provide coverage to 6 million lower-income Americans.

That was back in December. The promise to Collins was for a vote by the end of the year.

But the day after the tax vote, it was clear there would be no vote in 2017, something Collins acknowledged in a December 20 joint statement with Alexander, author of that separate bipartisan bill.

There were already indications Democrats and Republicans in the House might not be on board for the same version of the proposals. Instead, Collins and Alexander said they would introduce the stablilization bills early in 2018 and debate it around the massive "omnibus" spending bill lawmakers use to fund the government.

And that brings us to Thursday, nearly a quarter of the way into 2018. Republican leaders on Wednesday released the massive omnibus -- which is thousands of pages long.

What it doesn't have is any form of the bills Collins wanted to stabilize the Obamacare insurance market. And there's no talk, at the moment, of a new debate on it.

Here are a few ways to look at this:

Collins was effectively rolled; McConnell made his promise to get her vote without ever intending to follow through. Events conspired against her; McConnell made the promise, but then just couldn't find a way to schedule the vote. He tried. He really did, but an immigration debate, a guns debate and other things just got in the way.

Specifically, bipartisan agreement that the government should not just turn off its subsidy payments has turned into a fight over abortion. Republicans in the House wanted to add language barring federal funding for abortions to plans offered with government help on the private market. Democrats want to stick with current language that allows abortion coverage in these private plans, but requires a separate payment for such coverage.

So, even though Senate leaders made their promise and Trump told Collins in a phone call over the weekend he supports what's in her bill, for an unrelated reason -- abortion rights -- it will now not be in the omnibus spending bill. There's also a very real question over whether the Collins proposal would result in stabilizing the market, as the Portland Press-Herald in Maine made clear.

The end result (and the lesson for any lawmaker) is the same, however. Collins gave away the valuable thing she had and didn't get what she wanted in return.

She's not the only one. Democrats pledged and promised they would do something to help undocumented immigrants brought to the country as children who signed up for the Deferred Action for Childhood Arrivals program.

When he created that program, President Barack Obama promised the government would look out for them. When Trump ended the program, Democrats (and a lot of Republicans) promised to do something to fix the problem.

But when it became clear that public opinion as turning away from them, Democrats gave in, agreed to re-open the government in exchange for a debate later on.

Unlike Collins, Senate Minority Leader Chuck Schumer got his debate on immigration. It lasted a week and yielded no legislation, despite some bipartisan proposals. There was an opportunity to add protections for Dreamers in the omnibus, too, but they were also left out.

Again, the lesson here is that if you really want something in Washington, you're going to have to use up everything you've got in order to get it. And you're going to have to get it in hand before you give away your leverage.

Because the days of grand bipartisan debates in which lawmakers hash things out on the Senate or House floor are something of a myth at the moment.