Hashemi puts a deadline on pulling the Sunnis out of Maliki's government?

On CNN just now, Nick Robertson reported that Tariq Hashemi, the Sunni VP and top Sunni mainline politician, reiterated his threat to pull the Sunnis completely out of the Iraqi government if constitutional reforms aren't immediately undertaken.

This could completely demolish Maliki's government by removing any claim of non-sectarianism.

AP reports that the deadline for constitutional changes is May 15.

I assume this is the imposition of a deadline on the threat first voiced on Apr. 30.