Hours before President Barack Obama is to give a high-stakes health care speech tonight, U.S. Sen. Chuck Grassley, R-Iowa, warned him to steer clear of attacking Republicans.

On a conference call with Iowa reporters this morning, Grassley said Obama was elected to "lead this effort."

"It would be a mistake tonight for the president to blame Republicans for not going along with legislation that puts the government in charge of health care and adds to the deficit," he said.