Donald Trump best not bring up Bill Clinton's sex scandals at the second presidential debate with Hillary Clinton – because "you're never going to beat the Clintons in the mud," former House Speaker Newt Gingrich said.
In an interview on ABC News' "Powerhouse Politics" podcast, Gingrich said the political couple have far more experience as "gutter-fighters."
"You're never going to beat the Clintons in the mud; it's not possible," Gingrich said, according to excerpts released by ABC News.
"They're the best gutter-fighters we've seen in our lifetime."
"I mean you have to go back to Richard Nixon to find anyone with the potential to fight with her," he added. "So you've got to stay above her. You've got to say, 'Look, I'm going to beat you on jobs, I'm going to beat you on trade, I'm going to beat you on taxes.' I thought what he did last time in not bringing it up was to his advantage."
Gingrich has written he believes Trump won the first debate, but told ABC News more preparation for the second matchup wouldn't hurt.
"At a tactical level, he's not nearly as good as a debater," he said. "It wouldn't take much for him to be 20 or 30 or 40 percent better than he is now."
"He's an amateur, and he's a businessman," Gingrich added. "He's never going to match up with a Yale lawyer who's spent her entire lifetime trying to be glib.”
Trump said Tuesday he held his tongue responding to charges of sexism from Clinton at the first debate, out of respect for Clinton's daughter Chelsea, who was in the debate audience Monday night.