More than 30 Democratic senators joined with nearly all of their Republican colleagues on Monday to end the brief government shutdown. Their decision, framed by leaders as a strategic retreat, comes backed with a pledge from Majority Leader Mitch McConnell that he will open the floor to debate, and votes, on the fate of Dreamers in the coming weeks.

Activists roared their disapproval as Minority Leader Chuck Schumer made it public. Their main concern: Democrats have no mechanism to enforce McConnell's stated "intention" and no known reason to believe the House would take up legislation passed in the Senate.

And then there is the question of how President Donald Trump will respond. He's sent mixed messages on what he wants, sometimes vacillating from hour to hour. Now he'll have weeks to consider (and reconsider) his position.

But even as the broader impasse continues, the shutdown is nearly over. What comes next -- and how does this end? Here a few possible outcomes, broadly sketched, for a lasting immigration deal:

1) DACA expires without a fix

Their decision to change tactics so abruptly speaks volumes about Democratic resolve -- at least in the Senate -- on delivering for DACA recipients.

Let's first consider the hard political realities -- and potential calculations -- that would follow a failure to strike a deal.

Dreamers and DACA are broadly popular. Some 80% of Americans polled support some kind of deal to extend or entrench the current protections. If the March deadline hits and ICE agents begin pulling Dreamers out of their homes, schools or workplaces, Republicans risk suffering a significant public relations hit. Mass protests would follow, along widespread civil unrest. Whatever remains of Trump's self-styled dealmaker persona would disappear.

Also, it's worth considering this from Trump's chair. He was elected on a promise to crack down on illegal immigration. Could he reason that his base would take pleasure in seeing DACA blow up? That's also hard to say. But there would be plenty on the right, like the hardline immigration hawks in and around the White House, who would surely see it that way, even if most of the party has said publicly the program should be codified.

2) The easy out: Democrats trade a DACA deal for border wall money

For months, this appeared to be the path of least resistance. Both sides would walk away from a deal like this unhappy (well, Democrats would be much more unhappy and immigration activists would be incensed), but they could also tout the half they won on and downplay the part they didn't.

A handful of very important details would also color the response. For example, would DACA recipients receive a path to citizenship or just permanent legal status? And what about their parents? The Graham-Durbin compromise would have given some kind of protection the parents of Dreamers, too, though the specifics appear negotiable.

And then there's the wall. The Democrats' funding number would come in quite a bit lower than what Trump envisions. If it's the amount he wants -- in the neighborhood of $20 billion -- then the White House could claim a major win and deliver on one of Trump's foundational campaign promises.

Still, this would be an opportunity lost for more traditional immigration hawks. They want to use their considerable, if likely fleeting, power to reframe the debate and remake legal immigration too. This scenario would preserve the status quo on family unification and the diversity lottery.

3) A wider agreement: Democrats trade DACA for concessions on the wall and new legal immigration restrictions

This is a bit of a wild card, but would probably look something like the deal Graham and Durbin brought to Trump a couple weeks ago.

That proposal would have taken care of Dreamers, provided a negotiated number of border wall dollars, moved to restrict the family unification process (or "chain migration," as some call it) and almost certainly shut down the diversity lottery. In place of those legal immigration programs, some new process would be established, one designed to favor migrants with certain work skills or educational backgrounds. The lottery spots could be reallocated to people in the country under temporary protected status.

A deal along these lines would, again, allow both sides to return to their supporters and claim some kind of victory. Democrats, though, would have a much harder sell. Activists will be infuriated and division in the party's caucus on Capitol Hill would come into even starker relief.

Republicans, meanwhile, could fairly declare success in fundamentally changing the apparatus and underlying principles that guide the US immigration system.

4) Republicans allow a vote on a clean Dream Act in the House and Senate

This is Democrats' preferred path and one they've been seeking for some time, but also the least likely endgame, given Republicans' control of Washington. It would correspond, nominally, to Trump's promise -- one of many -- that a "bill of love" be passed to protect DACA recipients from mass deportations.

Still, it's hard to imagine any scenario in which there aren't strings attached to a vote on the DREAM Act, legislation first offered by Democratic Rep. Luis Gutiérrez back in 2001. This past summer, the most recent Senate iteration was introduced by a bipartisan pair, Sen. Lindsay Graham, the South Carolina Republican and Dick Durbin, the Illinois Democrat and minority whip.

The current pickle came about a) because, for more than a decade, the DREAM Act failed and failed and, b) in June 2012, the Obama administration created DACA, or Deferred Action for Childhood Arrivals, an executive action that offered conditional and temporary relief for undocumented immigrants brought into the country illegally as children. The executive action doesn't offer a path to citizenship or any permanent legal status. Instead, those eligible can apply for protection from being deported and work authorizations.

The one major plus here for Republicans is that, with a proper appropriations bill, they could deliver on promises to up military spending and other priorities written into their budget.