The Iraq war is to blame for high gas prices as its cost has weakened the dollar and driven oil speculation, Sen. Claire McCaskillClaire McCaskillUnder pressure, Dems hold back Gorsuch support Overnight Defense: General warns State Department cuts would hurt military | Bergdahl lawyers appeal Trump motion | Senators demand action after nude photo scandal The Hill’s Whip List: Where Dems stand on Trump’s Supreme Court nominee MORE (D-Mo.), a national co-chair of Barack ObamaBarack ObamaThe Memo: Winners and losers from the battle over health care Ex-Trump aide: Tillerson is ‘part of the swamp’ Rand Paul takes victory lap on GOP health bill 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 McCainMcCain says he hasn't met with Trump since inauguration Overnight Defense: General warns State Department cuts would hurt military | Bergdahl lawyers appeal Trump motion | Senators demand action after nude photo scandal Senate lawmakers eye hearing next week for Air Force secretary: report MORE--we can never leave Iraq," McCaskill said. See the video below.