Nancy Erickson, the Senate secretary, initially rejected Burris' appointment Monday because his certificate of appointment was missing the signature of Illinois Secretary of State Jesse White.

CNN: Feinstein says Burris should get Senate seat

Reid said that he is waiting for a ruling from the Illinois high court on whether Illinois Secretary of State Jesse White needs to sign the certificate of appointment for Burris.

CNN: Democrat: Blagojevich 'called our bluff' on Senate pick

Democrats expect Burris to show up on Capitol Hill on Tuesday with a certificate of appointment signed by Blagojevich but missing the signature of Illinois Secretary of State Jesse White, according to the Democratic source and a Democratic Senate leadership aide.

CNN: Burris to meet with Dem leaders, source says

On Monday Senate officials ruled that Mr Burris's appointment was not legal because his certificate has not been signed byIllinois's secretary of state, as well as the governor, as the rules require.

ECONOMIST: American politics