The leaked 2005 video showing Republican presidential nominee Donald Trump bragging about groping women was "vile," said Larry Kudlow, an informal advisor to the Trump campaign and a CNBC senior contributor.
But Kudlow sees the fallout since Friday's release of the tape abating somewhat, after Sunday night's debate. "His campaign is like a stock looking for a bottom. I think the campaign found a bottom. He will have some tomorrows. But he's still got a very difficult uphill climb."
Trump apologized for the comments during Sunday's debate, dismissing them as "locker room talk."
Kudlow, a former aide to President Ronald Reagan, said Monday there were moments over the weekend when he doubted whether to continue to support Trump. "The 'vile' tape, as I call it, is inexcusable," he said. "I was absolutely furious."
Democratic nominee Hillary Clinton "definitely has the upper hand" in the campaign, Kudlow said, but added he remains in favor of Trump's overall economic and tax cut plan, which he helped draft. "I wish he would sell it better," he said.
"I won't vote for Mrs. Clinton. I expect to vote for Mr. Trump," Kudlow told "Squawk Box" and "Squawk on the Street."
"I hope Mr. Trump gets his act together," he said. "But if he continues to drop into these rabbit holes, I'll write in Mr. Pence," referring to Trump's vice presidential running mate Indiana Gov. Mike Pence.
During the second presidential debate, Kudlow said Trump took a big chance bringing up past "Bill Clinton infidelities."
"I think [Trump] threaded the needle, if that's the right metaphor. And I think this deflated Mrs. Clinton quite a bit. She was not the same," Kudlow said. "I'm going to give him a small [debate] victory on points."