Shortly after House Speaker Paul Ryan took to CNN to say that he's not yet ready to endorse Donald Trump, the presumptive Republican presidential nominee, Trump replied with this doozy of a statement:

New @realDonaldTrump statement responding to @SpeakerRyan: "I am not ready to support Speaker Ryan's agenda." pic.twitter.com/hGk4no2HyJ — Sahil Kapur (@sahilkapur) May 5, 2016

It's a stinging rejection for Ryan. This afternoon, the House speaker appeared to be setting preconditions on his support for Trump. Trump would have to be a true conservative. He'd have to commit to principles of limited government and adherence to the Constitution. He'd have to be slightly less alienating toward Hispanics.

"In effect, Paul Ryan is urging Trump to run the campaign that Jeb Bush or Marco Rubio would have run — to be an orthodox conservative tax-cutter and spending-cutter, while trying to win over enough Hispanic voters to actually get to the White House," Vox's Andrew Prokop explained.

Trump is saying, in effect, "Yeah, I'm not going to do any of that." This puts a lot of pressure on Ryan. On the one hand, endorsing Trump without any concessions makes him look weak and without influence in the party. On the other hand, it'd be exceptionally awkward and basically unprecedented for a major congressional leader to not endorse the party's presidential nominee — especially when there's really no third-party option he can endorse instead.

If nothing else, the exchange bodes ill for the legislative productivity of a Trump administration. If he wins the general, he can expect a Senate majority under Mitch McConnell and a House one under Ryan — but from the looks of things, cooperation with the latter could prove very difficult.

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