Senators Grill Petraeus and Crocker

Gen. David Petraeus and U.S. Ambassador to Iraq Ryan Crocker testified before the Senate Tuesday, facing a more difficult grilling -- and far deeper sense of skepticism, especially among Republicans -- than they did during their Monday testimony before the House.

Surprisingly, the Democratic presidential candidates who were given the opportunity to ask questions as members of the Senate Foreign Relations and Armed Services Committees were overshadowed by some very skeptical senior Republicans.

Republican Sen. John Warner of Virgnia -- the former chairman of the Senate Armed Services Committee -- offered a polite but devastating appraisal of strategy in Iraq.

"Are you able to say at this time if we continue what you've laid before the Congress here as a strategy do you feel that is making America safer?" Warner asked.

"Sir, I believe that this is indeed the best course of action to achieve our objectives in Iraq," Petraeus said.

"Does that make America safer?" Warner asked again.

"Sir," Petraeus said, "I don't know actually."

The general said he was too focused on the mission at hand in Iraq to focus on that larger question on the minds of so many Americans.

Warner, a former secretary of the Navy, who announced two weeks ago that he would not seek re-election next year, was clearly fed up.

"Success in Iraq for Iraqis as well as our own goals centers around a successful national reconciliation process," Crocker said.

"That's what's been said at this table for a long time sir," Warner said, "and with respect it hasn't happened."

Later in the hearing Petraeus tried to walk his response back -- "I think the answer really, to come back to it, is yes," he said. But Warner later told reporters that the general's answer "was an extraordinary moment. Sometimes those moments are best, as they say, a photograph or a picture can tell a thousand words. Each person that watches that has to decide for themselves what was crossing that very fine man's mind."

Warner was one of several Republicans voicing skepticism that military success in Iraq mattered in the face of little political progress.

"This progress may be largely beside the point, given the divisions that now afflict Iraqi society," said Sen. Dick Lugar, the ranking Republican on the Senate Foreign Relations Committee.

Sen. Chuck Hagel, R-Neb., a longtime conservative critic of the president's war policy, asked, "Are we going to continue to invest American blood and treasure at the same rate we are doing now? For what? The president said let's buy time. For what?"

Responded Crocker, "The security situation has improved. That gives you an environment when you can start working on meaningful national reconciliation."

Senators struggled to get an answer to their questions.

When would the Iraqi government be able to achieve reconciliation? Asked Sen. Bill Nelson, D-Fla.

"I can't give you any timelines, dates or guarantees," said Crocker.

How long did the administration anticipate needing troops in Iraq? Asked Sen. Joe Biden, D-Del., the chairman of he Senate Foreign Relations Committee. "I'm trying to get an accurate estimate."

"In terms of concrete things like force levels, as Gen. Petraeus said, neither of us believe we can see beyond next summer," Crocker said.

Biden is one of five presidential candidates at today's hearings. Only one -- Republican Sen. John McCain was steadfast in his support for the general and the surge.

"Congress must not choose to lose in Iraq," McCain said, "and I will do everything in my power to ensure that we do not."

But that did not seem the majority view today.

"We have now set the bar so low ... to the point where now we just have the levels of intolerable violence that existed in June 2006, is considered success and it's not," said Sen. Barack Obama, D-Ill..

Sen. Hillary Clinton, D-N.Y., -- who like Warner, Lugar, Hagel, Nelson and Biden, voted to authorize use of force against Iraq in October 2002 -- told the general "you have been made the de facto spokesman for what many of us believe to be a failed policy."

Clinton accused the general of dodging a question first posed by Biden earlier in the day about how long U.S. troops will remain in Iraq.

"If in fact the circumstances on the ground are exactly what they are today in March of next year, will you recommend the continuation of somewhere between 130,000 to 160,000 troops being shot at killed and maimed everyday?" Clinton pressed Petraeus.

"I would be very hard pressed at that time to recommend a continuation," Petraeus responded. But, he said, "It's an awfully big hypothetical and it is not something that I would want to try to determine right here right now about a point a year from now."

ABC News' Z. Byron Wolf and Matt Jaffe contributed to this report.