Senate Republicans are openly seething over the White House’s treatment of John McCain, casting a pall over the party ahead of a rare lunch with President Donald Trump the caucus is hosting on Tuesday.

The White House’s refusal to apologize for an aide joking about McCain‘s failing health is threatening to undermine what should be a feel-good moment for the caucus.

“Just out of common decency they should apologize. And the person who said it should apologize. It’s wrong,” said Sen. Rob Portman (R-Ohio).

With a potential deal with North Korea in the works, the economy humming and Trump following through on his vow to pull out of the Iran deal, Republicans were feeling more upbeat about the administration than they had in months. But the morbid joke by communications aide Kelly Sadler last week, delivered at a staff meeting and promptly leaked to the press, made them wonder when the administration is going to start treating McCain with more respect.