Trump has endorsed in 15 Senate contests to date. While roughly half are for incumbents who are expected to cruise to the GOP nomination, he’s also waded into other nomination fights where his imprimatur was once thought to be determinative. So far, it hasn’t worked out that way.

In Alabama, where Trump remains extremely popular, Rep. Mo Brooks has struggled despite Trump’s endorsement. Brooks, a veteran congressman who lost in a 2017 Senate primary bid, has raised less than half of the $3.7 million his primary opponent Katie Britt has received. Britt has also earned the endorsement of the state’s largest farm organization, the Alabama Farmers Federation — a group that represents one of Trump’s key constituencies…

Despite Trump’s endorsement of Kelly Tshibaka, the former commissioner of the state’s Department of Administration, Murkowski has jumped to a 20-point lead in the race and has more than 10 times the amount of cash on hand.

In North Carolina, 52 percent of Republicans last month said the former president’s preference would make no difference in who they support, according to a Public Opinion Strategies poll conducted for Pat McCrory, the former governor whose opponent, Rep. Ted Budd, has the Trump endorsement.