Republicans are facing rebellions from Mississippi to Arizona that could imperil their grip on Congress, as Mr. Moore’s win emboldens populist challengers.
The adviser, Roger J. Stone Jr., also said he told the House Intelligence Committee that he had not colluded with Russians or seen any collusion by Trump associates.
Mr. Moore, a firebrand former chief justice of the Alabama Supreme Court, overcame efforts by top Republicans to rescue his rival, Senator Luther Strange, defeating him on Tuesday in a special primary runoff, according to The Associated Press.
Senator Bob Corker, the Tennessee Republican who chairs the Senate Foreign Relations Committee, announced on Tuesday that he will not seek re-election.