Democrats experienced another instructive flare-up in intra-party tensions last week, this time over a spending bill that did not include protections for DACA recipients.

Many Democrats supported the bill in order to avoid a government shutdown, planning to take up the task of negotiating DACA protections only weeks later in January. The delay was enough to rankle hardline liberal immigration activists.

"Even before the Senate vote, a group of House Democrats burst into the office of Sen. Charles E. Schumer (D-N.Y.), the Senate minority leader, demanding an explanation," reported the Washington Post. "Protesters shouting 'Shame on Kaine!' briefly occupied the office of Sen. Tim Kaine (D-Va.), who said he voted for the measure to prevent a partial government shutdown and protect federal employees."

The Post report quoted Murshed Zaheed, the political director of CREDO Action, saying, "Every single Democrat who voted for the continuing resolution just voted to deport 'dreamers' and leave kids without access to health insurance."

"Those 32 Democrats who voted for this bill voted to deport Dreamers,” Angel Padilla, policy director of the Indivisible Project, claimed in a statement.

Grassroots pressure seemed to influence the vote of Sen. Dianne Feinstein, D-Calif., which was switched to oppose the bill amid pressure from her primary opponent. In September, House Minority Leader Nancy Pelosi was shouted down during a speech by self-identified "undocumented youth" who demanded a "clean bill" on the Dream Act.

And therein lies the problem.

On immigration, energized activists in the Democratic base are so inflexible that party leadership could be forced out of making a deal with Republicans that actually achieves protections for Dreamers.

Take this excerpt from the Post's article:

At his year-end news conference Friday, Senate Majority Leader Mitch McConnell (R-Ky.) said a DACA working group would get “some floor time in January,” but he cautioned that Republicans wanted DACA coupled with reforms “that improve the legal immigration system” — an unreasonable demand for activists who have demanded a “clean Dream Act” and no less.

With Republicans in control of Congress, Democratic leaders interested in protecting Dreamers will have to negotiate with Republicans. But their base is clearly going to make that difficult.

Democrats have reason to be optimistic about their prospects in the midterms next November. The party's united disapproval of President Trump is allowing it to sweep some of these reckonings under the rug for the time being. But though it may be more easily minimized for now, Democrats' increasingly radical base is not a problem that is going anywhere in the long term.