Senate Democrats are under increasing pressure to block a critical government funding bill this week if they don’t win concessions on protecting Dreamers from deportation, a plan that raises the chances of a partial government shutdown by the weekend.

House and Senate lawmakers are expected to consider a continuing resolution that would fund the government for a few weeks. It would be the fourth “CR” Congress has passed to authorize spending in fiscal 2018 and results from a longstanding disagreement between Democrats and Republicans over long-term funding levels and other matters, including how to handle the Dreamers.

Republicans are expected to support the CR, but House and Senate Democrats have begun signaling they plan to vote against it, citing the lack of progress on a deal to protect Dreamers in exchange for new border security and immigration reform provisions.

“Are we the kind of country that targets young people who were brought here as kids — people who are American in every way but on paper?” Sen. Kamala Harris, D-Calif., tweeted last week. “I believe we aren’t, but time is running out for us to prove it. Congress must act to pass the Dream Act now.”

While the House can pass the measure with only GOP support, the Senate has a 60-vote threshold that gives Democrats the power to filibuster. And the liberal Democratic base is pressuring Senate Democrats to vote against the CR unless it includes language to protect the Dreamers.

The progressive group Indivisible is urging Democrats to sign a “Dreamer Pledge” that essentially promises to vote against the next CR unless it “has the Dream Act attached.”

The Dream Act is legislation that would not only permanently legalize the so-called Dreamers, but would provide a pathway to citizenship.

Pressure from the base, including demonstrations in the office of Senate Minority Leader Chuck Schumer, D-N.Y., wasn’t enough in December, when 17 Senate Democrats voted in favor of a short-term spending bill that now expires on the 19th.

This time, it’s not clear whether Democrats will unify behind blocking the bill, and even President Trump seems aware of the risk.

“I don’t know” if there will be a shutdown, Trump said on Monday.

Sens. Ron Wyden, D-Ore., and Tammy Duckworth, D-Calif., are among a small group of Democrats so far who have signaled they would vote “no” on the CR. Forty-one Democrats can block the bill, and there are 47 Democrats and two Independents who might decide to do just that.

Schumer has not signaled this week whether he will tell his caucus to \ the CR. He has repeatedly insisted that Dreamer protection be included in the bill, which isn’t likely at this point.

“The bottom line is, it must go in a must-pass bill. And the only must-pass bill that we see coming down the road between now and March 5th is this bill,” Schumer said, referring to the CR. “So we continue to believe, insist, that it be in this bill.”

A deal on Dreamers, however, could take weeks, if not longer, some Republicans said. Democrats are resisting an accord that includes significant money for border security or major changes to the visa lottery or chain migration policies.

Negotiations appeared to break down late last week, when a small bipartisan group presented Trump with a proposal that Trump and other Republicans viewed as a giveaway to Democrats with little in the way of tough border security.

Sen. Dick Durbin, D-Ill., then told the press, Trump, in their private meeting, called African nations and other countries "shitholes" whose residents shouldn't be let into the country.

Trump is now attacking Democrats, their stance on immigration, and the spending deal.

“Senator Dicky Durbin totally misrepresented what was said at the DACA meeting,” Trump tweeted Monday. “Deals can’t get made when there is no trust! Durbin blew DACA and is hurting our Military.”

Democrats know they risk political damage if they vote against the spending bill and a partial government shutdown occurs.

In October 2013, Republicans refused to vote for a government spending measure, resulting in a partial shutdown for 16 days that caused GOP poll numbers to temporarily plummet.

Senate Democrats are likely to be particularly sensitive of getting pegged with the blame for a shutdown as 10 lawmakers in their caucus face difficult re-election prospects in states Trump dominated in the 2016 election.

“So Democrats are now threatening to shut down the government if they don't get amnesty for millions of illegal immigrants,” Sen. Tom Cotton, R-Ark., tweeted. “Let's see how that works out for them, especially in places like WV, IN, MO, ND, & MT.”