Speaker Paul D. Ryan delivered his party’s weekly address on Friday — a rarity — giving a peek at the House Republican agenda that he and his colleagues will begin to roll out next week.

That agenda was originally supposed to counter Donald J. Trump, whose views often stand apart from the party’s policy traditions. But now that Mr. Ryan has officially endorsed his party’s presumptive nominee, he says that his policy ideas will magically become Mr. Trump’s, and that the nominee will help advertise them this fall and eventually promulgate them from the White House.

The six policy task forces in the House will release their prescriptions one at a time over a course of Fridays this summer, under the broad title: “A Better Way.” But perhaps it should be called “A Benighted Way.”

Despite Mr. Ryan’s efforts to take some control, however, here are four reasons Mr. Trump, not the House speaker, is far more likely to set the Republican agenda this summer at his party’s convention and into the fall campaign.