Michigan, with 156 delegates, has scheduled a Jan. 15 primary. Democratic Party rules prohibit states other than Iowa, New Hampshire, Nevada and South Carolina from holding nominating contests before Feb. 5.

Michigan officials anticipated the action by the Democratic National Committee’s rules panel. But Michigan Democratic Chairman Mark Brewer said before the vote he didn’t think the delegates would be lost for good.

Although Brewer is optimistic, Mark Grebner, a political consultant with East Lansing-based Practical Political Consulting Inc., isn’t as positive.

Grebner criticized the Michigan Democratic Party for its actions. While he is unsure whether the party has constructed a deal with the national party, he said the move was not in the state’s best interest.

“There’s no reason to believe there’s any genius here,” Grebner said.

Saturday’s vote further diminishes Michigan’s Democratic primary. All the major Democratic candidates have already agreed not to campaign in either Michigan or Florida because the states violated party rules.

The Republicans have stripped half the delegates from New Hampshire, Florida, South Carolina, Michigan and Wyoming for scheduling early primaries and caucuses. Republican rules don’t allow any states to hold nominating contests before Feb. 5.

The Republicans, however, haven’t set any restrictions on campaigning in states that violate party rules. That has some Democrats concerned they could lose votes in Florida, the fourth largest state, and Michigan, the eighth largest.

Democratic candidates will now need support from at least 2,026 delegates to secure the nomination.

The panel gave Michigan officials 30 days to schedule a later vote, but Brewer said the state will stick with Jan. 15.

Zack Colman contributed to this article.