Hagel: McCain on "thin ground"

Sen. Chuck Hagal, along with Sen. Jack Reed, appeared on CBS's "Face The Nation" to discuss their recent Middle East trip with Barack Obama.

From CBS/AP:

(Hagel) criticized the McCain campaign for its latest television ad attacking the Democratic candidate.

The ad blasts Obama for not visiting wounded troops during his visit to Germany. Obama has said he chose to cancel a visit to a military hospital there after consultations with the Pentagon, due to concerns that such a visit might be seen as using wounded troops for political purposes.

The McCain ad, which contains footage of Obama bouncing a basketball before U.S. military personnel in Kuwait, implied that Obama was being disrespectful to troops by making "time to go to the gym" during his overseas trip while at the same time cancelling a visit with wounded troops.

"Seems the Pentagon wouldn't allow him to bring cameras," the ad insinuates.

The commercial began airing after a week of news coverage of Obama appearing with foreign leaders and speaking to cheering European crowds. The McCain campaign has suggested that Obama preferred that audience to wounded American soldiers.

"John McCain is always there for our troops," the ad said.

Obama's campaign called the new accusation "wildly inappropriate."

Hagel stated that McCain was "treading on some very thin ground here when he impugns motives, and when we start to get into 'You're less patriotic than me, I'm more patriotic.'

"They're better off to focus on policy differences," he said, "It's just not responsible to be saying things like that, again, if for no other reason than for the good of this country and the world.

I agree with what he's saying, but I don't know if I've ever heard the phrase "treading on thin ground" before. Shouldn't that be "on thin ice"? Or maybe Hagel is referring to "dangerous ground", which would make sense in this context also. But "thin ground" seems like a mixed metaphor. Taken literally, if McCain is on thin ground, then the danger is that he'll break through the surface and crash below to what, more solid ground? Or mud? Maybe molten hot magma? This is bugging me. Somebody explain it to me, please.

Other than Hagel's obvious mangling of a stale cliche, he was spot on about the McCain campaign's outrageous charges. Sen. Reed also strongly condemned the actions by McCain. I think if this is happening now and it's only July, I can't wait to see what they'll pull when the REALLY get desperate!