Absolutely. They can’t amend the Constitution through ordinary means. Which is why they’ve installed a bunch of extreme right-wing Supreme Court justices who can interpret the Constitution however they want to benefit right-wing extremists.
Here’s a completely plausible scenario: Donald Trump orders ICE to deport any child born here to non-citizen parents in complete defiance of the court order. The district court judge gets really annoyed and issues criminal contempt rulings against the head of DHS and ICE for disobeying an order of the court. Trump orders DHS and ICE to ignore the court and promises pardons to anyone facing criminal contempt charges.
Because the SCOTUS has ruled “core powers” are “absolutely immune” and the pardon is an explicit power granted to the president with no limitations, he can use the pardon power literally however he wants, including as part of a criminal conspiracy to break the law.
And bam, full blown constitutional crisis because the SCOTUS basically neutered the entire judicial branch and gave the president dictatorial powers.
Democrats don’t usually force shutdowns because the people most likely to suffer under a shutdown are federal, state, and local government employees, people who work in academia, and people in major metropolitan areas, all of whom make up a significant portion of the Democratic base. It doesn’t make sense to force a shutdown if your own voters are just going to blame you for the disruption it causes to their lives anyway.
Now there’s far more to lose, and Trump is going to get the blame for it. Shutdown for a few weeks to protect a few hundred thousand federal workers for at least a year is a pretty safe gamble when you’re not likely to get blamed for the short-term disruption anyway.