Senate Majority Leader John Thune can afford to lose three Republican senators and still pass the bill, and there are more than that, right now, who have problems with it. Like the House, he will have to balance the concerns from moderate and conservative members of his conference.

There are as many factions among Republicans in the upper chamber as in the House. Both chambers have to agree on the final product. It won’t be easy.

House Republicans were jubilant after muscling through President Trump’s tax and immigration package by a single vote. But across the Capitol, senators were more cautious.