The brain drain from departing House Republicans with policy expertise had sparked worry among party insiders even before Speaker Paul D. Ryan announced his plans to retire.

Now, the extraordinary attrition, along with a potentially brutal upcoming midterm campaign, is enough to send the GOP into panic mode.

Ryan’s exit won’t simply open up the top job in the House, something the November elections may accomplish anyway. It also means House Republicans will need to find a political leader who can herd an often fractured conference and raise gobs of campaign cash.

Even more difficult to fill, the Wisconsinite’s departure leaves a vacancy for a leader who can serve as the intellectual standard-bearer and, however muffled, a sometime moral voice of reason for the party of President Donald Trump on Capitol Hill.

Though Ryan’s successor, whoever that may be, could well grow into those aspects of the job, no one on the short list has that level of policy gravitas. House Republicans may find themselves waiting.