Sen. John KerryJohn KerryGlobal Magnitsky's power to protect Obama must act to protect Palestinian youth Tough choice for vulnerable GOP senators: Embrace or reject Trump MORE (D-Mass.) joined Al GoreAl GoreThe Trail 2016: Dems struggle for unity Al Gore not picking sides in Dem race Moulitsas: Can Hillary pick Gillibrand as her veep? Yes. MORE this week in blaming Denver's altitude for President Obama's poor performance in the first presidential debate.
"I personally really do believe that the altitude may have had something to do with it," Kerry told the Sante Fe New Mexican.
Gore previously blamed the high altitude for Obama's showing, a claim mocked widely by Republicans and comedians.
Kerry also attributed Obama's "bad night" to indecision on his strategy for his first match-up with GOP nominee Mitt Romney.
"I … think he wasn't settled in his own mind completely on his own strategy," Kerry said. "And I think that held him back. I was surprised, obviously."
Kerry, who played Romney in mock debates against the president, seemed to imply that Obama might have been considering other last-minute approaches to the first debate, since Obama had been on his game the night before.
Kerry was in New Mexico this week to help Rep. Martin HeinrichMartin HeinrichOvernight Energy: Senate Dems block energy, water bill a third time Bison declared national mammal The myth of favorite son and daughter vice presidents MORE (D-N.M.) campaign for the Senate. He said keeping control of the Senate in Democratic hands is critical to preventing the Tea Party from pushing its agenda through Congress.
"The Tea Party is setting the agenda of the United States Congress through [Sen.] Jim DeMint in the Senate and the fear they put into the hearts of their Republican colleagues," he said. "And they block everything. They blocked the farm bill, they blocked the highway bill, they blocked the infrastructure bill, they blocked the veterans' jobs bill recently."