Congress won't shut down the government Friday. The House and Senate just passed a spending bill to keep the government open for one week, and President Trump is expected to sign it. That means that next Friday they're going to go to the brink all over again as they try to pass a spending bill that will last through this fiscal year, or Sept. 30.

The good news: Budget experts think Congress should be able to stave off a shutdown next week, as well. The players, including Trump, have all pushed aside their demands, hoping to avoid more drama. For now.

The bad news: In avoiding one trap, Congress could be setting itself up for an even bigger one in a few months. By getting nothing this time around, lawmakers on either side and the president may be less open to negotiation next time -- especially at the end of September, when Congress has to pass a spending bill for a full year.

That means that as the likelihood of a shutdown in April decreases, the likelihood of a shutdown in September increases. To better understand why, let's run down three scenarios for how the upcoming spending debates (on May 5 and in September) could play out:

The Crisis Averted Scenario

Republican and Democratic leaders bought themselves a little more time Friday to draft spending legislation that not everyone in Congress likes but that enough people in both parties can live with to pass a majority in both chambers. The goal is good, not perfect.

A spending bill designed to avert a crisis does not have any political lightning rods that could repel Democrats, like defunding for Planned Parenthood or including funding for Trump's U.S.-Mexico border wall. Nor does it have anything that conservative House Republicans won't live with, like massive pending increases.

In this scenario, Congress passes a spending bill by midnight next Friday, President Trump signs it, and a government shutdown is averted for the next few months.

How likely is this? Right now our experts say this scenario is the most likely. The last thing Republican leaders want is another government shutdown on their watch, so they're going to do whatever they can to keep it from happening. The rest of the party seems eager to avoid a shutdown, too: On Friday's House vote for a one-week extension, just 16 House Republicans voted against it, less than half of the 35/40-member conservative House Freedom Caucus that usually opposes these kinds of bills.

The Crisis Scenario, version 1

Congressional budget leaders draft a spending bill that both Democrats and hard-right Republicans in the House Freedom Caucus loathe (it increases domestic spending too much and defense not enough, it doesn't do enough for Obamacare or it cuts Obamacare too much, and on and on and on). Congress can't pass something in time, and the government shuts down.

(Or they pass yet another bill extending government funding — and the shutdown threat — by a week.)

How likely is this? Our experts say this scenario is still a possibility. (The factions that shut down the government in 2013 and nearly again in 2015 are still very present in Congress). But it's a diminishing possibility because, this time almost all sides seem to be willing to negotiate. This time.

The Crisis Scenario, version 2

Congress passes a spending bill, but Trump says he won't support it because it doesn't contain enough of his priorities (funding for his U.S.-Mexico border wall being top of the list). Or Trump demands those priorities be in the spending bill, and outraged Democrats vote against it. Either way, the government shuts down.

How likely is this? A week ago, it was very likely.

By Monday, Trump had backed off his proposal. This was significant. It means Trump will finish his 100 days at 0-4 on legislative promises he made.

The dynamics in the first two scenarios aren't new: Torn between increasingly stubborn, polarized parties, Congress has faced a shutdown threat at least once or twice a year for the past couple of years.

With less than a week to pass a new spending bill, negotiations between the White House, Republicans and Democrats are ramping up to avoid a government shutdown on April 29. (Jenny Starrs/The Washington Post)

It's the third scenario — what Trump wants — that's totally new. The unpredictability of the president is what threw many of our budget experts' predictions from “probably no shutdown this time” to “anything could happen" in September.

“It's going to come down to what Trump wants,” said nonpartisan budget expert Stan Collender. “And it's not clear that he knows what he wants.”

The September Crisis Scenario

Well, we can guess what the president will want in September, when Congress must pass a spending bill for the entire fiscal year 2018: a lot.

Trump won't get money for his wall this time. Trump has also given up on the cuts in domestic programs and the increase in defense spending he asked for. Basically, said Steve Bell, a former Senate GOP budget aide now with the Bipartisan Policy Institute, "the president is going to get zero out of this negotiation."

That only increases the chances he's going to demand everything a few months from now. "I really don't know when the president is going to say: 'I need a victory,'" Bell said.

As soon as Trump — or anyone else with leverage in this — puts a foot down on any number of the issues above, we'll be on shutdown watch all over again. That's not going to be Friday, and it's not likely to be next week, but a standoff could be coming sooner than we realize.

Graphics by Darla Cameron. Icons by Shashank Singh and Chelsea Carlson for the Noun Project.