Former New York City Mayor Rudy Giuliani on Tuesday evening called it "silly" for President Obama to take on his eventual Republican presidential competition rather than stay focused on the economy.

“We don’t want a president to become a commentator on 10 Republican candidates,” Giuliani said on CNN’s “Piers Morgan Tonight.” “We want the president of the United States to have his own plan for leadership, which he doesn’t have.”

Obama has been in campaign mode this week on his Midwestern bus tour focusing on jobs and the economy. While in Iowa, Obama spoke out about the Republican contenders for the 2012 presidential nomination, slamming Mitt Romney in a reference to healthcare policy and pledging to be “ready” for the competition in 2012.

Obama’s bus tour speeches have also criticized Congress for putting party ahead of country and slowing down progress with politics in Washington.

“This guy’s fighting with Republicans in Congress when he should be trying to figure out how to straighten this problem out,” Giuliani said. “He was elected to straighten out the economy, and he’s made it much worse.”

Giuliani, who has flirted with his own presidential bid in 2012, compared Obama’s record unfavorably to his own as mayor.

“I took over NYC when it was in a terrible fiscal mess. I didn’t complain about the Democrats, I didn’t complain about the liberals; what I did was I laid out a plan, I staked my reputation on it, and it worked,” he said.

“I think [Obama has] been the worst president we’ve had since before Jimmy Carter,” Giuliani said. “I think Jimmy Carter had a better sense of the economy than Barack Obama does.”

Giuliani also slammed Obama for continuing to blame former President George W. Bush for the economy. “Three years into it, I couldn’t blame my problems on my predecessor when I was the mayor,” Giuliani said.