Shifting to foreign policy after two days of hammering the Illinois senator over their differences on health care, Clinton paired two of Obama's campaign statements to support her conclusion.
"He wavers from seeming to believe that mediation and meetings without preconditions can solve some of the world's most intractable problems to advocating rash, unilateral military action without the cooperation of our allies in the most sensitive part of the world," Clinton said in a speech at The George Washington University.
The former first lady has sharply criticized her rival for the Democratic presidential nomination for saying during a televised debate last summer that he would be willing as president to meet with the leaders of Cuba, Iran and other hostile nations without preconditions. He reiterated that willingness last week.
"We simply cannot legitimize rogue regimes or weaken American prestige by impulsively agreeing to presidential talks that have no preconditions," Clinton said. "It may sound good, but it doesn't meet the real world test of foreign policy."
Obama also has said he would be willing to send U.S. troops into Pakistan if there were "actionable intelligence" that the country is harboring terrorists.
Anticipating Clinton's criticism, Obama's foreign policy advisers held a conference call with reporters before her speech.
Top Obama adviser Susan Rice said the New York senator had shown poor judgment on a range of issues, including voting to authorize the invasion of Iraq and supporting legislation declaring the Iranian National Guard as a terrorist organization.
"Those are critical foreign policy judgments. They are judgments that any candidate should be held accountable for. And obviously we look forward to Senator Clinton's explanation of how and why she got those critical judgments wrong," Rice said.
Hoping to slow Obama's candidacy before primaries in Texas and Ohio next week, Clinton painted a picture of a dangerous world in need of seasoned and wise U.S. leadership. She portrayed Obama as a national security novice and suggested he would need a "foreign policy instruction manual" to keep the country safe.
Again, she compared her Democratic rival's foreign experience to that of President Bush upon taking office in 2001.
Voters already have seen the "tragic result" of electing a commander in chief with little experience in national security and global affairs, she said. "We can't let that happen again. America has already taken that chance one time too many."
On a campaign trip through Ohio on Monday, her husband, former President Clinton, urged undecideds among a crowd in Portsmouth to vote for her "if you believe that the fact of change is more important than the feeling of change."
Referring to Obama campaign mailings that his wife criticized over the weekend, the former president said at Shawnee State University: "A lot of the mailings that have been sent out against her on health care and NAFTA are pure garbage."
NAFTA, the North American Free Trade Agreement, is unpopular in Ohio, which has lost blue-collar jobs to other countries. The treaty was signed by President George H.W. Bush in 1992; the legislation to implement it was signed by Clinton in 1993.
Hillary Clinton said Obama's ads unfairly portrayed her as a supporter of the agreement which she says she is working to change.
Over the weekend, Obama told an Ohio audience: "She was saying great things about NAFTA until she started running for president."
Hillary Clinton also responded to Obama's flyers on NAFTA by placing automated phone calls Monday to Ohio voters with a message accusing Obama of distorting her record.
"NAFTA has hurt Ohio families, and I have a plan to fix it," Hillary Clinton says in the call. "My opponent does not. I'll appoint a trade prosecutor to enforce our trade agreements, and crack down on China's unfair trade practices. I'll eliminate tax breaks for companies that ship our jobs overseas, and invest in creating good jobs right here in Ohio."
The campaign also began mailing its own flier describing her trade proposals and criticizing Obama. "American workers can't afford Barack Obama ," her flier states.
Obama's campaign, in turn, accused the Clinton camp of misrepresenting his views.
