LARGO, Maryland (AP) — With just five days to go before Americans can begin signing up for health care under his signature law, President Barack Obama on Thursday ridiculed Republican opponents for "crazy" doomsday predictions of the impact and forecast that even those who didn't vote for him are going to enroll.

With polls showing many Americans still skeptical of the law known as "Obamacare," the president went back to the basics of explaining how nearly 50 million uninsured Americans will be able to buy coverage in new government-run exchanges while mocking Republicans for trying to block its implementation. "The closer we get, the more desperate they get," Obama argued.

"The Republican party has just spun itself up around this issue," Obama said. "And the fact is the Republicans' biggest fear at this point is not that Affordable Care Act will fail. What they're worried about is it's going to succeed."