While Cruz is a hero to many conservatives, some candidates are leery of appearing with him because he is a polarizing figure who could turn off independents and moderate Republicans.

Two of Cruz’s potential rivals for the GOP presidential nomination in 2016, Sens. Rand Paul (R-Ky.) and Marco Rubio (R-Fla.), are in higher demand, traveling widely to the battleground states that will determine control of the Senate in November.

Political strategists say the disparity illustrates how Paul and Rubio can appeal to a broader swath of the electorate, which is key in a general election.

“It’s almost exactly a year ago to the day when [Cruz] led to the government shutdown. That appealed to a narrow and narrowing wing of the Republican Party,” said Rich Galen, a Republican strategist. “For a lot of people that was over the top and they’re not comfortable with him.”