Some of the Republicans who know Newt Gingrich best said this week that it is too soon to write off the former Speaker’s presidential candidacy following his much-maligned criticism of a House GOP plan to overhaul Medicare.

But in separate interviews Wednesday, Sens. Saxby Chambliss and Johnny Isakson suggested that this might not be the last time their fellow Georgian gets himself into hot water with conservative activists and Republican primary voters.

Both Republican Senators also were complimentary of Peach State businessman Herman Cain, saying that the other GOP candidates in the field underestimate the wealthy long shot at their peril. Cain set up a presidential exploratory committee in January and is expected to announce this month that he will run.

The Senators said they planned to remain neutral in the GOP presidential primary for the foreseeable future.

“Newt’s the smartest politician I know,” said Chambliss, who was first elected to Congress in the 1994 Republican revolution led by Gingrich. “He’s a great communicator, he has really good ideas and I think he’d made a very good president. He’s known from day one he’s got issues he’s got to overcome. But, shucks, because he is such a smart guy, he understands all of that, and there are bumps in the road in any campaign — and he’s going through one of those bumps.

“If this is the worst hill he has to climb in the primary, I’d say he’s in pretty good shape,” Chambliss added, referring to statements Gingrich made Sunday on NBC’s “Meet The Press” in which he referred to the House GOP plan to overhaul Medicare as “right-wing social engineering” to be avoided. Gingrich has since apologized to the plan’s author, Budget Chairman Paul Ryan (R-Wis.), following days of withering criticism from a host of conservatives, including activists, elected officials and prominent pundits.

The Medicare proposal would revamp the federal health insurance program for seniors and the disabled. Users would instead buy private insurance, and Medicare would help subsidize the cost by making payments to the chosen plan. The proposal would only affect those age 54 and younger; the current Medicare system would not change for those 55 and older.

Gingrich’s penchant for provocative commentary is partly why the former Speaker has been productive as a conservative thinker, Isakson said.

“He does have some great ideas. Like all of us, every now and then one or two of them aren’t as good as we think they are. But if you aren’t thinking, you don’t need to be in this job,” said Isakson, who was elected to Gingrich’s old House seat following his resignation from Congress after the 1998 midterm elections. “Like anybody with a long career in public life, with that comes a lot of perceptions and past experiences, which he’s being confronted with now that he’s gotten into the race. But you can’t underestimate him as an individual and a politician.”

Isakson also is particularly familiar with Cain. The former CEO of the Godfather’s Pizza restaurant chain ran against Isakson in 2004 in an open GOP Senate primary. Isakson, who won that race, said it was an achievement for Cain that he finished second, ahead of then-Rep. Mac Collins.

“Herman’s a very articulate guy, he’s got a good business background. He’s a great speaker, and I know Herman well and have a high regard for he and [Gingrich] both,” Isakson said. “He was underestimated in the race he and I were in. It was a three-man race, and the incumbent Congressman who ran against me finished third.”

Chambliss offered similar praise for Cain, calling him a “really good guy” and a “really great communicator.”

Cain is a “bright guy, a good sound businessman. And, again, would make a very good president, in my opinion,” Chambliss said. “What I’m hearing from folks around the country is, ‘Gee, I didn’t know Herman Cain but I happened to see him in the debate, or heard him on TV the other day, and this guy’s got really good ideas, and he’s a comer.’ And, he’s going to get a really good look by a lot of people.”