The House voted this weekend to block the Trump administration’s handpicked Postmaster General Louis DeJoy from continuing changes to Postal Service operations that have contributed to widespread delays in mail delivery this summer. The House bill would infuse $25 billion into postal coffers, in part to handle the crush of mail-in ballots expected this fall. Senate leaders previously voiced support for some Postal Service aid, but the Senate is unlikely to consider the bill, which the president has pledged to veto after declaring it a “money wasting HOAX.”

Bipartisan outrage at postal delays led DeJoy to stop operational changes until after the November election. But Democrats remain deeply concerned that President Trump’s attacks on vote-by-mail — combined with DeJoy’s cost-cutting — will derail Americans’ confidence in ballot security and counting this fall.

Here are three takeaways from the House vote.

Messaging politics, with a twist

In many ways, the House action looks like a classic “message vote” — a roll call staged by party leaders solely to highlight differences between the parties. No one expects message votes to actually influence policy outcomes; the point is to force the other party to go on record against your party’s priority.

By calling House members back from their August recess during the coronavirus pandemic, Democrats were able to get headlines about how seniors and veterans aren’t getting their medications on time or how farmers are receiving dead chicks. The vote forced members of Congress to vote on the record about the Trump administration’s plans to undermine the overwhelmingly popular Postal Service. For Democrats, it was an easy “yea” vote: It signaled to those hit hardest by the delays, allied their party with the highly unionized postal workforce and called out the president for boasting that the cuts would derail mail-in voting.

And the GOP? With very few exceptions, legislators typically side with their party on message votes. Not this time. Over two dozen House Republicans defected, breaking with Trump and party leaders and siding with Democrats who were playing offense against the Trump administration. Not surprisingly, defecting GOP members hailed disproportionately from Democratic-leaning swing districts. Many had barely won their races in 2018. For some of them, the prospect of a 30-second attack ad in the fall elections might have raised the stakes.

Positioning for September negotiations

In response to the postal crisis, Senate Republicans last week floated a new version of their “skinny” pandemic relief bill, which provides far less emergency aid than Democrats’ House-passed Heroes Act. The Senate bill’s new version adds $10 billion for the Postal Service. But now that every Democrat and some endangered Republicans voted for the House’s Postal Service bill, Democrats have made it plain they won’t easily bend to GOP demands.

Whether or not Republicans are willing to bargain over emergency relief, the federal government’s fiscal year begins Oct. 1. The federal government will shut down if Congress and the president don’t agree to a stopgap spending bill that would fill government coffers at least until after the November elections. The effort to avoid a shutdown before a tightly contested presidential election is likely to motivate the White House to go to the bargaining table. The recent House vote and Senate counterproposal make it more likely that a stopgap bill will provide extra funds for the Postal Service, even over the president’s objections.

The limits of Postal Service “independence”

Finally, the brewing postal crisis is a stark reminder that “independent” government agencies can be steered by political principles.

On paper, the law treats the Postal Service as an “independent” agency. Congress and the president created it in 1970 in the wake of huge wildcat postal worker strikes. That new law removed the postmaster general from the president’s Cabinet. Instead, the law empowered the Postal Service Board of Governors to select a postmaster general.

In practice, as we’re seeing, presidents have not lost their ability to impose their agendas on the Postal Service. Through Treasury Secretary Steven Mnuchin, the president exploited the power to appoint postal governors, who then gave him Dejoy, his handpicked postmaster general. Given Trump’s personal vendetta against Amazon, the president has pushed the Postal Service to renegotiate delivery contracts with the company and other carriers, though there’s been no evidence of special treatment afforded Amazon. (Amazon founder and chief executive Jeff Bezos owns The Washington Post.) Conservatives have long aimed to privatize the Postal Service rather than operate it as a public good. And DeJoy surely was aware of the president’s opposition to mail-in voting, which DeJoy’s changes could impede.

Of course, presidents don’t have free rein to push around the Postal Service. Public opinion typically constrains presidents who attempt to act unilaterally. Postal delays hurt both red and blue states, especially rural areas represented disproportionately by Republicans. What’s more, the post office supports a highly visible, unionized and popular workforce with tentacles in every congressional district. Congress naturally got into the game.

No surprise that Democrats moved swiftly by message vote to slow down a president eager to mess with the post office.