Has Paul Ryan lost the sparkle he needs to sell the GOP's agenda?

Mr. Ryan’s fledgling speakership, which he once suggested would be one giant policy discussion, has instead been a series of extraordinary challenges. He has sought to be the voice of moral clarity for his party, even as Republicans fracture over the divisive candidacy of Donald J. Trump.

He has tried to ground himself in Republican policy as the country’s political axis has shifted after terrorist attacks and gun violence, and has taken to more populist economic views. Mr. Ryan, the country’s highest ranking Republican, seeks to maintain his stature in the party without alienating its Trumpian factions or its Romney-esque traditionalists.

His most basic legislative agenda — getting a budget and spending bills passed — has failed, killed off by his right flank. He has been through a month of altercations with Democrats over gun legislation, and now is forced to punish them for their sit-in on the House floor.

What would seem to be among his easier tasks — backing the presumptive Republican presidential nominee — has become a bizarre ritual of alternately denouncing and then supporting Mr. Trump, on an almost weekly basis. An attempt to pass a modest bill aimed at preventing terrorists from acquiring guns has been deeply resisted by many Republicans, even though their Senate counterparts want it.