House Republicans about to unanimously nominate Speaker Paul D. Ryan for another term as their standard-bearer recently got a not-so-subtle signal of who’d really united their party:

Red “Make America Great Again” hats were waiting on every seat.

The prominence of President-elect Donald Trump’s much-maligned campaign slogan was a clear departure from the image the party had projected before Nov. 8, when Ryan was staring down an insurgence for his refusal to campaign for Trump, and Senate Majority Leader Mitch McConnell and dozens among the rank-and-file were so exasperated by their nominee that they refused to even utter his name.

But it’s still unclear whether Trump can forge the relationship he will need with Congress to push through an ambitious, and vague, policy agenda — or whether he even wants to. He will also need to keep a lid on the divisions within the party.

Trump’s interactions with Congress have, until now, been so limited that it is impossible to know how he will relate to the institution after he is sworn in.