WASHINGTON — The list of hard-line immigration demands that President Trump said he needs to back protections for young undocumented immigrants triggered a furious response on Monday from Democrats and immigration activists, who gave no indication they were willing to strike any deal.

More important, it exposed a largely unspoken truth in the capital: Nearly a month after Democratic leaders and Mr. Trump celebrated the possibility of a bipartisan immigration deal, no such agreement appears on the horizon. Instead, any agreement that would shield about 800,000 young immigrants from deportation will depend on how far Democrats are willing to push the government toward a shutdown in mid-December, when a stopgap spending bill expires.

Representative Nancy Pelosi of California, the Democratic leader, strongly hinted that if Republicans did not have the unity to keep the government open, Democrats would offer their votes only at a steep price. Democrats almost always need to add their votes on spending bills because of defections from the most conservative wings of the Republican Party. That was the scenario that Democratic leaders were playing for when they insisted that a deal reached in September would fund the government only until Dec. 8.

“There is always in the background, what leverage do we have?” Ms. Pelosi said in an interview. “But it isn’t anything that has to be pronounced. It is there.”