"To stop the liberal Harry Reid-Barack Obama agenda, we must win the Senate Majority – and we can’t do that without Pat Roberts back in the Senate," Cruz said in a statement.
An NBC News/Marist poll released Sunday showed Roberts trailing Orman by 10 points. Orman has not said which party he would caucus with if the majority comes down to him.
Roberts is trying to shore up his support among Republicans of all ideological persuasions in the closing weeks of the campaign. He's already brought in Sen. John McCain (R-Ariz.), Sarah Palin and former Senate majority leader Bob Dole to stump with him.