State lawmakers approved the bill setting the earlier primary date this afternoon, and it could reach the desk of Gov. Jennifer M. Granholm, a Democrat, as early as tomorrow. Liz Boyd, a spokeswoman for Ms. Granholm, said that she will sign the bill. "Governor Granholm supports a primary that will make Michigan relevant in the presidential selection process," Ms. Boyd said.

But if state Democratic and Republican officials decide to abide by the earlier date, they'll be in violation of national party rules that restrict the number of states that are allowed to hold primaries before Feb. 5. And, Michigan Democrats are said to be considering whether to scrap the primary altogether and hold caucuses instead. The Democratic and Republican national committees have indicated they will sanction Michigan for holding an early primary. The D.N.C. has said it will take away all the state's national convention delegates, while the R.N.C. may refuse to seat half of them.