Members of Massachusetts' all-Democratic congressional delegation are condemning the sweeping Republican tax bill as a giveaway to the rich that will punish the middle class — a bill that was passed without a single Democratic vote.

Sen. Elizabeth Warren tweeted that Senate Republicans "gave a giant tax break to the rich and left everyone else holding the bag." Sen. Ed Markey called the bill "heartless and fiscally irresponsible."

At a town hall in Salem on Saturday, Rep. Seth Moulton was swift to criticize the bill as his constituents told him their concerns and worries about it.

"The Republicans in passing this tax bill in the middle of the night are throwing out the middle class, and they're throwing out the U.S. Constitution with it," said Moulton. "You don't pass a bill you're proud of in the middle of the night. You pass a bill you're ashamed of."

"It's really scary to witness and hear about what goes on each and every day. It's almost hard to believe at times," said Joyce LaRochelle of Danvers, who spoke for many in the crowd that filled an auditorium at Salem State University.

Kelli Strong, as well, said she had many concerns about the bill.

She's a veteran who's worried about a provision in the House version that would tax tuition grants as income. She says it would prevent her from finishing her post-graduate degree.

"It's going to make it impossible for working class and middle class people to go through higher education," she said. "And I'm wondering, what are you going to do to fix that? Because I can't afford to get a Ph.D. because it's going to be taxed three times on me."

But the reality, said Moulton, is that the Republicans control both chambers of Congress, and the White House.

"So what am I going to do? I'm going to make sure that Republicans aren't in charge in 2018 and 2020," he said.

The bill isn't law yet. Passage of the measure follows approval of a House version, and means Republicans may soon have a bill on President Trump's desk, giving him his first big legislative achievement.

The major rewrite of the nation's tax law laws would cut corporate taxes dramatically. Republicans are also selling it as a break for the middle class.

"The average taxpaying family is going to get a $2,200 tax cut. We doubled the standard deduction, we increased the childcare credit. This is very much oriented towards middle class tax relief, but also making sure our jobs are still here and in the United States and not somewhere else," said Senate Republican leader Mitch McConnell on ABC's "This Week."

That may be true, but the middle class tax cuts would expire in a few years, while the benefits for corporations would stay. Several independent studies conclude that the Senate tax plan would increase the national debt by at least a trillion dollars.

But the crowd on Saturday wasn't entirely in Moulton's camp. John Macauda of Peabody challenged Moulton over his opposition to the Republican tax plan, and then moved on to immigration, asking Moulton why he voted against deporting gang members involved with criminal activity.

Moulton did oppose a Republican bill aimed at deporting gang members due to concerns about due process rights, as did many Democrats.

"I'm going to address an even more controversial position that I have, which is why do I support they sanctuary city ordinance right here in Salem," Moulton said to Macauda.

For many of those in the crowd, this exchange was a reminder that a million Massachusetts voters supported Trump for president.

And while polls suggest that most Americans oppose the Republican tax plan, there's little or nothing Democrats like Moulton can do to stop it.