“He said, ‘You know in New Hampshire your numbers are dropping like a rock. John Kasich is going to catch you if you don’t fundamentally change the way you’re running your campaign and go out and be positive,’” Lewandowski said, as quoted by Politico. “Because it used to be that when people were leaving us they were going to Cruz but Cruz wasn’t playing in New Hampshire.”
Roe confirmed to the Los Angeles Times that that he had called Lewandowski, saying that “we needed Trump” to defeat other candidates in the Granite State.
Cruz polled relatively poorly with New Hampshire Republicans, and a Trump win in the state was seen as hurting Cruz's other competition at the time, like Sen. Marco Rubio (R-FL) and Ohio Gov. John Kasich (R).
Lewandowski said that the expanded field aided Trump, according to Politico, given that the other candidates saw only each other as competition and diverted their resources away from attacking him.
Roe, for his part, said at the panel that he tried to unite the rest of the Republican campaigns against Trump’s but “[t]hose calls went unanswered.”
Ahead of the Indiana primary, three months later, the Kasich and Cruz campaigns entered a shaky agreement not to spend money attacking each other. Trump won that state, and Cruz dropped out of the race the next day.