Five of the six the presidential hopefuls have long said they would not vote for any spending bill that does not include protection for hundreds of thousands of young undocumented immigrants brought to the country as children, who have been shielded from deportation by an Obama-era program that Mr. Trump rescinded. (The sixth, Ms. Klobuchar, also voted against the last short-term spending bill.)
But some red-state Democrats like Senator Joe Manchin III of West Virginia (a state Mr. Trump carried with nearly 68 percent of the vote) are equivocating, clearly worried that Democrats could take the blame for a shutdown if the spending bill does not pass.
“We’ve got 48 hours, and that’s a lifetime in the news cycle around here,” a nervous-sounding Mr. Manchin said Wednesday, as he hurried through the Capitol while avoiding reporters’ questions about whether he would vote for the spending bill.
“I want to keep the government open,’’ Mr. Manchin insisted repeatedly. “I’m just going to work and work and work to keep the government open.”
Republicans, watching some vulnerable Democrats squirm, are delighted, sensing an opportunity in what looks to be an otherwise dismal election year.
“The Democrats running in the 10 states that Donald Trump carried have all demonstrated an ability to get elected in Republican states, so they obviously have something going for them,” said Whit Ayres, a Republican strategist. “But having the Democratic Party veer further and further to the left makes their lives substantially more difficult.”
Democrats stood firmly together last year, when every Senate Democrat voted against repealing the Affordable Care Act and the Republicans’ tax overhaul. Senator Chuck Schumer, the Democratic leader, said Wednesday that his caucus is overwhelmingly opposed to the proposal by House Republicans to pair a stopgap spending bill with long-term funding for the popular Children’s Health Insurance Program.
“The revulsion toward that bill was broad and strong,” Mr. Schumer said, adding, “There’s very, very strong support not to go along with their deal.”
But Senator Chris Van Hollen of Maryland, who leads the Democratic Senatorial Campaign Committee, signaled that Democrats would not be voting in lock step this time. “I think every member will do what they always do, which is make a judgment as to what’s best for people in their state,’’ Mr. Van Hollen said.
The fate of the young, undocumented immigrants, known as Dreamers, has become a cause celebre on the left, and Democrats are under intense pressure from progressive advocacy groups to ensure that the Obama-era program, Deferred Action for Childhood Arrivals, or DACA, is enshrined into law.
About 780,000 Dreamers are protected by DACA, and Mr. Trump has given lawmakers until early March to pass legislation codifying it.
A federal judge last week ruled that for now, the administration could not end the program, and the government has resumed accepting renewal requests for it. But the Justice Department has said it will ask the Supreme Court to intervene and overturn the judge’s ruling.
The president and Republicans say they are for protecting the Dreamers. But they insist that those protections be paired with money for border security — including the border wall that Mr. Trump promised he would build — as well as provisions ending a visa lottery program aimed at bringing in immigrants from countries that do not send many people here, and limits on family-based migration, which critics call “chain migration.”
Liberal lawmakers like Ms. Harris, however, are demanding that Congress pass a stand-alone Dream Act (the letters stand for Development, Relief and Education for Alien Minors), which would shield the young immigrants from deportation with no strings attached.
“I’ve been very clear that we need to have a clean Dream Act, we need to take care of these kids,” Ms. Harris said. “There has been bipartisan expression that we should take care of them, and I see no reason why we should be playing politics with them or thinking of them as leverage for something else.”
Liberal advocacy groups, watching the maneuvering, are pleased.
“It’s been really good for progressives that there’s been kind of a race among potential presidential candidates to not just be on board, but be leaders on issues like Medicare for all, fighting for Dreamers and fighting against Trump’s giveaways to billionaires and giant corporations,” said Adam Green, a co-founder of the Democratic Change Campaign Committee, a liberal advocacy group.
“Anyone on the extended reaches of the presidential watch list who votes against the Dreamers isn’t doing themselves a favor in terms of getting onto the top of the watch list,” he added.
Mr. Booker, for one, is taking no chances. During a brief hallway interview in the Capitol this week, he delivered a rousing soliloquy in explaining why he would not vote for any spending bill that did not address the fate of the DACA recipients.
“These are American citizens in every single way but a piece of paper,” Mr. Booker said. “They are people who’ve served in our military; we should honor and respect that,’’ he added. “These are first responders; we should honor and respect that. These are people who have stood up for America, they are teachers and servants, and I’m not going to leave them behind.”
Continue reading the main story