War with Iran would be a hard sell to the American people, the Republican presidential candidate John McCain said on Tuesday. "I believe we can act with nations with values and principles that we hold dear and exercise enormous pressure -- diplomatic, trade, financial," Senator McCain told MSNBC's "Hardball." However, the senator did not entirely rule out the possibility of a military confrontation, but added that any decision would have to overcome the current "credibility gap" which was created after President George W. Bush justified the invasion of Iraq in 2003 on the existence of Iraqi weapons of mass destruction. To do so, McCain said that he would have to make an "even more convincing argument that [war is necessary] because of [the] failure" to find Iraqi WMDs. In an interview with JTA earlier this week, the presidential hopeful was pessimistic about the value of negotiations with Iran, but did not rule out speaking with Iranian leaders, excluding Iranian president Mahmoud Ahmadinejad. "Our ambassador in Iraq, I believe, has been there three times," McCain said. "There's been Iranians there in Baghdad. They've had conversations. There's plenty of ways to communicate." "I think that our failures for nearly four years [in Iraq] obviously [have strengthened Iran," the senator added. "But I believe that [this] is being reversed as the surge succeeds, and I think that the Iranians are very possibly going to step up their assistance to the Jihadists, because they don't want us to succeed in Iraq." ROB ESHMAN / LA JEWISH JOURNAL [JTA] contributed to this report.