The Iraq war is to blame for high gas prices as its cost has weakened the dollar and driven oil speculation, Sen. Claire McCaskillClaire McCaskillSenators question need for HHS cyber office Overnight Cybersecurity: Obama DHS chief defends Russian hack response | Trump huddles on grid security | Lawmakers warned about cyber threat to election systems We must protect our most vulnerable from financial fraudsters MORE (D-Mo.), a national co-chair of Barack ObamaBarack ObamaRahm Emanuel: Trump changed GOP base Trump: Hillary Clinton colluded with Democrats to defeat Bernie Sanders Trump breaks with tradition, forgoes Ramadan dinner MORE's presidential campaign, said today.

"We cannot economically afford to keep borrowing two to three billion dollars a week from China," McCaskill said on MSNBC. "That's why gas prices are so high. People are speculating in commodities because nobody wants to go near our dollar. We cannot--it is unsustainable to continue to prop up, in the middle of a civil war, an Iraqi government that will not step up and do what they need to do."

McCaskill appeared on MSNBC this afternoon to discuss Obama's planned trip to Iraq and Afghanistan. McCaskill is a national co-chair of Obama's campaign. When host Monica Novotny pressed McCaskill on Obama's plan to withdraw from Iraq despite recent security gains, McCaskill pushed back by saying the war's cost is unsustainable.

"If you can't leave Iraq when it's stable and you can't leave Iraq when it's not stable, that means that we're stuck with George Bush and John McCainJohn McCainFrustrated Dems say Obama botched Russia response Coats: Trump seemed obsessed with Russia probe The Hill's Whip List: Senate ObamaCare repeal bill MORE--we can never leave Iraq," McCaskill said. See the video below.