Vice presidential candidates Sens. Sarah Palin and Joe Biden clashed on the economy, foreign policy, energy and global warming in their first and only debate on Thursday evening at Washington University in St. Louis, Mo.

Palin, the Republican, made repeated references to herself and GOP presidential nominee Sen. John McCain as "mavericks," while Democrat Biden took every opportunity to paint himself and Sen. Barack Obama, the head of the ticket, as the only candidates capable of bringing change to Washington, D.C. Here are some highlights of their debate.

Wall Street Meltdown: The debate opened with questions about the economy and the Wall Street bailout package making its way through Congress. Palin said McCain would "put partisanship aside" to help solve the nation's economic crisis, while Biden countered that Wall Street had run wild during eight years of Republican rule in the White House. Palin also said McCain had sounded the alarm years ago about Fannie Mae and Freddie Mac, two now-disgraced mortgage industry giants, but other lawmakers had ignored his warnings. Biden saw it differently, saying McCain's first words after the crisis erupted were, "The fundamentals of the economy are strong." (Watch Video: Financial Blame)

Iraq War: Biden ripped into McCain's position on the Iraq war and his refusal to accept a timeline for the withdrawal of U.S. troops. Palin called such a timetable "a white flag of surrender." She also said Biden had once supported McCain's view of the war, "and I know again that you opposed the move that he made to try to cut off funding for the troops and I respect you for that. ... I don't know how you can defend that position now but -- I know that you know, especially with your son in the National Guard." (Palin has a son who just deployed to Iraq.) Biden would have none of it: "John McCain voted to cut off funding for the troops. Let me say that again. John McCain voted against an amendment containing $1 billion, 600 million dollars" for protective equipment that is "protecting the governor's son and, pray God, my son and a lot of other sons and daughters. He voted against it." (Watch Video: Iraq Strategy)

Greatest Dangers: The candidates were asked whether they though Iran or Pakistan represented a greater threat to U.S. and global security. Pakistan is under intense U.S. pressure to combat militants responsible for rising attacks at home and in neighboring Afghanistan. Its faltering efforts so far have been met with a blur of suicide bombings that have killed nearly 1,200 people since July 2007, according to Army statistics released this week. And the U.N. declared the Pakistani capitol unsafe for the children of its international staff Thursday and ordered them out. (Watch Video: Iran Or Pakistan?)

Global Warming: Palin declined to attribute the cause of climate change to man-made activities alone, but she said that as the governor of Alaska, she had seen the effects of global warming in oerson. "There is something to be said also for man's activities, but also for the cyclical temperature changes on our planet," she said, adding that she didn't want to argue about the causes. Biden said the cause was clearly man-made, and added, "If you don't understand what the cause is, it's virtually impossible to come up with a solution." (Watch Video: Climate Change)

Vice Presidential Power: Biden pounced when Palin said she agreed with Vice President Dick Cheney that the office should function more as a part of the legislative branch, and less under the control of the president. "I'm thankful the Constitution would allow a bit more authority given to the vice president if that vice president so chose to exert it in working with the Senate and making sure that we are supportive of the president's policies," Palin said. Said Biden: "Cheney has been the most dangerous vice president we've had probably in American history. The idea he doesn't realize that Article I of the Constitution defines the role of the vice president of the United States, that's the Executive Branch. He works in the Executive Branch. He should understand that. Everyone should understand that. ... The only authority the vice president has from the legislative standpoint is the vote, only when there is a tie vote. He has no authority relative to the Congress." (Watch Video: Vice Presidential Power)

Campaign Promises: When asked what campaign promises they might have to withdraw owing to the nation's financial downturn, Biden said, "The one thing we may have to slow down is the commitment we made to double foreign assistance. ... We are also going to make sure that we don't go forward with the tax cut proposals of John McCain" for people making more than $250,000 a year, and for oil companies. Palin used her time on the question to argue with Biden over tax breaks for oil companies. Moderator Gwen Ifill asked her the question again and she said, "There is not. I've been at this, what, five weeks? There hasn't been a whole lot that I've promised." (Watch Video: Campaign Promises)

Gay Marriage: Both Obama and McCain oppose gay marriage, but also oppose efforts to amend the U.S. Constitution to ban gay marriage, preferring to leave the question up to individual states. Biden said he and Obama support laws that seek to provide same-sex benefits because "it's only fair." Palin, supporting McCain, said the two would not support laws that discriminate against same-sex couples. (Watch Video: Gay Marriage?)

Ever Disagree? How would a Biden administration be different from an Obama administration, were Obama to be elected president but unable to complete his term? "If it were to happen, I would carry out Barack Obama's policies," Biden said, putting an emphasis on passing laws to help middle class Americans, ending the war in Iraq and winning the war against terrorism. Palin said, "We're a team of mavericks. What do you expect? We're not going to agree 100 percent on everything." And she said drilling for oil in the Alaska Wildlife Refuge, which McCain opposes, is a point of disagreement. But she said she would be committed to carrying out McCain's agenda. (Watch Video: Ever Disagree?)

Achilles Heel: When asked about what her Achilles Heel might be, Palin instead talked about why she thought McCain picked her to be on the Republicans ticket. She said that "it was my connection to the heartland of America. Being a mom, one very concerned about a son in the war, about a special needs child, about kids heading off to college." Biden admitted he had a lack of discipline and a lot of passion. And then he pointed out that he, too, knew about family struggles. He became visibly choked up when he said, "I understand what it's like to be a single parent. When my wife and daughter died and my two sons were gravely injured, I understand what it's like as a parent to wonder what it's like if your kid's going to make it." (Watch Video: Achilles Heel?)