"The testimony of the president is not material to this case," U.S. District Judge James Zagel said today in issuing the ruling.
Zagel said he might be willing to reconsider the issue during the course of the trial — which is set to begin June 3 — if Blagojevich's lawyers submit more evidence that they need Obama's testimony.
The ruling came on the sameday that Blagojevich's onetime chief of staff and running buddy Lon Monk pleaded guilty today for a second time to crimes tied to the Blagojevich administration.
Monk, 51, admitted to conspiring to solicit a bribe from a horse-racing businessman for a campaign contribution in exchange for getting a bill signed.
Monk is cooperating with investigators and pleaded guilty again after prosecutors filed new charges, crafted to deal with a possible future ruling from the U.S. Supreme Court that experts say could strike down the federal "honest services" fraud statute.
Monk has agreed to serve 24 months in prison.