Ralph Nader, liberal activist and two-time third-party presidential candidate, lambasted President Obama in a Wednesday interview, and called for a liberal alternative to challenge in him in the 2012 presidential campaign.
"He has no fixed principles," Nader said, of Mr. Obama. "He's opportunistic -- he goes for expedience, like Clinton. Some call him temperamentally conflict-averse. If you want to be harsher, you say he has no principles and he's opportunistic."
"He's a con man," Nader continued. "I have no use for him."
Nader urged a progressive candidate to challenge Mr. Obama for the presidency in 2012, and said that while he wasn't altogether disallowing the possibility of running himself, it was time for a new progressive leader to step forward.
"Obama's position has been that the liberal, progressive wing has nowhere to go, therefore they can't turn their back on the administration. But a challenge will hold his feet to the fire and signal that we do have somewhere to go," Nader said.
"I'm not foreclosing the possibility [of running]... There are just other things to do," he continued. "And it's time for someone else to continue. I've done it so many times. When I go around the country, I'm telling people they need to find somebody."
In a Tuesday letter to Mr. Obama, Nader expressed his discontent with the president's decision to compromise with Republicans on tax cuts for America's highest earners - an issue that has inspired a firestorm of criticism from many liberals.
"It has become a widely-noticed habit of yours [Obama's] to concede or to adopt both the Republican terms of policymaking and Republican policies and programs," Nader wrote. "For many of your 2008 voters, this [deal] will indeed be the last straw for any active support they might have considered providing you ... [and] will signal even greater capitulations to the Republicans during the next two years," the letter continued.
The 76-year-old Green Party leader - who has long been an advocate of issues including consumer protection, environmentalism, and humanitarianism - called the tax cut deal "the last straw."
"There will be a primary," he said. "Just a question of how prominent a person [challenges the president]."
Lucy Madison is a political reporter for CBSNews.com. You can read more of her posts here. Follow Hotsheet on Facebook and Twitter.