Updated

The White House is enlisting former President Bill Clinton's help in explaining President Obama's health care law as a key phase of the reform nears.

Clinton will speak about the law on Sept. 4 at his presidential library in Little Rock, Ark. His remarks come less than one month before the public can start signing up for the health care exchanges, which will be crucial to the law's success or failure.

Obama and Clinton have become increasingly close in recent years. After last year's Democratic national convention, Obama aides dubbed Clinton the "secretary of explaining stuff" because of his convention speech's broad defense of the president's policies.