Four Democratic candidates withdrew from Michigan's Jan. 15 presidential primary, undercutting the validity of the contest's earlier date.
Sen. Barack Obama of Illinois, former Sen. John Edwards of North Carolina, and New Mexico Gov. Bill Richardson filed the necessary paperwork Tuesday — the deadline to withdraw from the ballot, said Kelly Chesney, spokeswoman for the Michigan Secretary of State's office.
Additionally, Sen. Joe Biden of Delaware said in a statement that he was bypassing Michigan's primary, calling it a beauty contest.
"Today's decision reaffirms our pledge to respect the primary calendar as established by the DNC and makes it clear that we will not play into the politics of money and Republican machinations that only serve to interfere with the primary calendar," said Luis Navarro, campaign manager for the Biden for President Campaign.
All of the Democratic candidates already have agreed not to campaign in Michigan because the state broke Democratic National Committee rules when it moved its primary ahead of Feb. 5.
Other Democratic candidates had until the end of the day to decide if they will stay on the ballot.
Party rules say states cannot hold their 2008 primary contests before Feb. 5, except for Iowa on Jan. 14, Nevada on Jan. 19, New Hampshire on Jan. 22 and South Carolina on Jan. 29.
The calendar was designed to preserve the traditional role that Iowa and New Hampshire have played in selecting the nominee, while adding two states with more racial and geographic diversity to influential early slots.
As punishment, the DNC has vowed to strip Michigan and Florida, which scheduled its contest on Jan. 29, of their delegates.
From NPR reports and The Associated Press