Democratic presidential candidate Martin O'Malley pounced on Hillary Clinton's failure to take a clear stance on the Keystone XL pipeline Monday.

"Real leadership means forging public opinion. Real leadership means taking stands on critical issues," the former Maryland governor said in a statement. "Our climate, our home, is in trouble if we do not act. Ducks and dodges — as we're seeing from other candidates — won't help: What we need is action. I know where I stand on Keystone XL and I have a plan to end our reliance on fossil fuels by 2050."

If elected to the Oval Office, O'Malley reiterated that he would double America's energy efficiency within 15 years with the goal of wasting less energy and creating more jobs. He would also renew investments in the physical and intellectual infrastructure to power a clean energy economy and create a new, clean energy job corps.

"And on day one, I would reject projects like Keystone XL, and deny new permits for drilling in Alaska, the Arctic and off our coasts," O'Malley said.

O'Malley has been pushing an aggressive climate agenda since mid-June, but this was Clinton's first time speaking on the issue. When asked about the Keystone pipeline by the press after her speech on green energy Monday, Clinton said she would "refrain from commenting because I had a leading role in getting that process started and I think we have to let it run its course."

O'Malley was less equivocal, saying, "Oppose Keystone XL, and ask all other presidential candidates to do the same."