Arizona’s Tom O’Halleran is exactly the sort of House Democrat you might expect to vote for Republican tax cuts. But he didn’t. Photo: Tom Williams/CQ-Roll Call,Inc.

With all the focus on how many House Republicans might defect on the Trump Tax Bill that was passed today, it has largely gone without comment that once again, not a single House Democrat crossed the aisle to support a major piece of GOP legislation. That was also the case on the two huge health-care bills the House voted on earlier this year.

Yes, it’s true that all three bills in question were packaged as budget-reconciliation legislation designed to pass both houses of Congress without Democratic support. But that hasn’t kept Democrats from climbing onboard Republican bandwagons in the past.

Consider the most obvious parallel to the Trump tax-cut legislation: the first and biggest of George W. Bush’s tax-cut proposals, in 2001. It, too, was set up as a budget-reconciliation bill. But when it came to the House floor 13 Democrats voted for it. And 28 House Democrats voted for the final conference report on that bill. (12 Senate Democrats voted for the bill as well).

What’s changed since then? Well, quite a few things. The parties are more polarized generally, with Republican extremism repelling many centrist Democrats, even as the number of centrist Democrats has sharply declined (the iconic Blue Dog Coalition had 35 House members in 2001, and just 18 today). There was no budget deficit in 2001. And perhaps most importantly, in 2001 the GOP president was George W. Bush, who seemed generally interested in attracting Democratic votes and even sanctioned a few tax-bill deals Democrats wanted. Donald Trump’s interest in bipartisanship is entirely abstract and hypothetical.

Still, progressives who are wary of centrist Democrats ought to be impressed by today’s Democratic solidarity in Congress. In the House, there are 12 Democrats representing districts that went for Donald Trump last year; none of them have defected on major legislation. In the Senate, there are famously ten Democrats representing states won by Trump. Yes, some of them, like other Democrats, have voted for some of Trump’s Executive- and Judicial-branch nominees. But on the big health care, budget, and tax bills, so far they’ve stuck with their leftier colleagues. In a party constantly beset by divisions over presidential candidates, political strategies, and labels, that’s an accomplishment.