President Trump's former campaign manager told Fox News' "Hannity" Thursday night that Republican lawmakers "should have held tough" and resisted the appointment of a special prosecutor to lead the FBI investigation into possible connections between the Trump campaign and Russian officials.

"There is no evidence of any wrongdoing. There is no evidence of collusion. There is no reason for this," Corey Lewandowski told host Sean Hannity. "The bottom line is, it’s a political witch-hunt. It is not necessary.

"The Republicans are weak on this thing. They should have held tough," Lewandowski added. "They should have been stronger."

Lewandowski also pointed out that Trump remained popular with Republican voters in some of the key states he won this past November.

"[Trump's] numbers are higher by eight points in Ohio today. They’re higher than they were on Election Day in Iowa," he said. "His approval rating among Republicans is 80 percent in the state of Pennsylvania, and what that tells you is you have to fight back."

Lewandoski suggested that the president was being ill-served by his media surrogates, saying that Trump "needs the surrogates on TV who can go out and push back against this false narrative that there’s not anything getting done in Washington.

"The bottom line is, in the first 120 days, he’s been more successful than most administrations have been in four years."