By Sahil Kapur WASHINGTON — A weak performance for Republicans in Tuesday’s elections has sparked new waves of anxiety in the party, and strategists are now urging their candidates to change course on how they discuss the issue in order to win competitive races next year. Three GOP sources told NBC News that party operatives fighting to win control of Congress are making a concerted push Wednesday to encourage Republicans to make clear to voters, in speeches and TV ads, that they don’t favor ...