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The government shut down is entering its third day, with no clear end in sight. Lawmaker spent much of the weekend publicly blaming the other side, while privately trying to come up with any deal that the other side can support.

It's not clear they will strike one any time soon.

“We have yet to reach an agreement on a path forward that is acceptable to both sides,” Senate Minority Leader Charles E. Schumer (D-N.Y.) told reporters as the Senate headed toward a noon vote Monday on whether to keep the government open.

Lawmakers are navigating a hornet's nest of competing issues and egos. Here are the four most significant unanswered questions that Congress must figure out to end a shut down:

1. Will Democrats agree to on a deal to talk about immigration only after the government reopens? This is probably the biggest question mark, because it gets to two issues at the heart of this shut down: immigration and trust.

Moderates in the Senate are trying to get both side to agree to a deal to fund the government now and agree to debate a bill to protect immigrants brought to the country illegally as children, or “dreamers,” later.

But Democrats are very wary that Republicans can't be trusted to hold up their end of the bargain. In both chambers, Republicans control what comes up for a vote. And even if a deal could pass the Senate, immigration deals have languished in the more conservative House of Representatives.

Plus, the White House has refused to offer any guarantees about what happens after the government reopens. They've drawn a hard line: open the government, then we'll talk about talking about legislation.

2. What does President Trump do? There's a strong case to make that Trump's indecisiveness was a major factor in this shut down.

Democrats said that in the days leading up to the shut down, twice they offered taxpayer money for Trump's border wall in exchange for protections from dreamers, and twice, he seemed receptive, then suddenly rejected it. (Once with profanity heard round the world.)

As my colleagues on Capitol Hill report, Democrats' trust in the president to negotiate is lower than low:

Schumer on Sunday said that in the hours before a shutdown, Trump “picked a number for the wall, and I accepted it.”

“It would be hard to imagine a much more reasonable compromise,” he added. “All along, the president saying, ‘Well, I’ll do DACA, dreamers, in return for the wall.’ He’s got it. He can’t take yes for an answer. That’s why we’re here.”

3. Will rank-and-file Democrats even accept a deal that includes funding for Trump's border wall? In the House, top Democrats seem split. Rep. Luis V. Gutiérrez (D-Ill.) told ABC that he would reluctantly do that: “I think the wall is a monumental waste of taxpayer money. Having said that . . . if that’s what the hostage takers [demand for] the dreamers, if that’s their ransom call, I say pay it.”

But when House Minority Leader Nancy Pelosi (D-Calif.) got asked by reporters if she would accept a deal that gave $20 billion to start Trump's wall, her answer was simply this: “Oh, come on.”

It's easy to see why Pelosi considers that idea absurd. Trump's wall has become a symbol of everything the left despises about the president. Even border state Republicans have been reluctant to support a wall.

The public is skeptical, too. Majorities of Americans oppose a border wall (63 percent), according to a new Washington Post-ABC News poll. That includes 68 percent of independents and 86 percent of Democrats.

Those numbers pose a risk for Democrats who put the border wall on the negotiating table to end this shut down: Are they successfully negotiating one popular thing (getting a deal to protect dreamers) at the expense of something extremely unpopular (funding Trump's border wall)?

4. Even if the government reopens, now what? Even when the government reopens, it will likely be with just a short-term spending bill that doesn't change funding levels from last year. Congress has been relying on a lot of those lately. This would be the fourth one of these short-term spending bills Congress has had to pass since the fiscal year started in October.

The stop-and-start nature  has a number of normally reliable Republicans frustrated, so frustrated that they voted against last week's short-term spending bill on principle.

“I’m tired of it. This is the fourth one we’ve done, and you’re killing the military,” Sen. Lindsey O. Graham (R-S.C.) told reporters last week.

Put another way: Congress can't agree right now to fund the government for a couple weeks, let alone for the rest of the fiscal year.

Reopening the government likely won't solve any of the institutional problems that got Congress in this mess in the first place: debates over where to raise spending, funding for disaster aid, the opioid crisis, partisanship and competing factions within parties. Which means: As soon as we get out of this shutdown, Congress is potentially at risk for another.