Updated

Nothing beats having a former adversary make your case, and the White House has taken to following Arizona Republican Senator John McCain's one-time economic adviser Mark Zandi. He thinks the president's jobs bill will add nearly two million jobs and knock one percentage point off the nation's unemployment rate, now at 9.1 percent.

As the president makes a final push for the bill, he's relying on economists who see the 447 billion dollar stimulus package as a shot in the arm for a staggering economy. "This isn't just my belief," he said in his weekly media address, "this is what independent economists have said. Not just politicians. Not just people in my administration. Independent experts who do this for a living have said that this jobs bill will have a significant effect for our economy and middle-class families all across America."

Accurate growth predictions can prove vexing for even the best economists, though. Back in 2009, just before Barack Obama was sworn into office, Zandi analyzed another economic stimulus plan, the American Recovery and Reinvestment Act. The massive spending package, a combination of infrastructure projects, tax incentives and social outlays, would, he wrote, "...ensure that real GDP returns to its previous peak by the end of 2010." The unemployment rate, he predicted, would fall to 7.84 percent in 2011. That's nearly two points lower than the current level.