For the next three weeks, the integrity of American democracy is in the hands of people like Norman D. Shinkle, a proud Michigander who has, until recently, served in relative obscurity on the state board that certifies vote results.

But now Mr. Shinkle faces a choice born from the national election turmoil created by President Trump, his preferred candidate, for whom he sang the national anthem at a campaign rally in Lansing last month.

Mr. Shinkle’s duty, as one of two Republicans on the four-member board, is to validate the will of Michigan voters and certify President-elect Joseph R. Biden Jr.’s victory ahead of the Electoral College vote on Dec. 14. Yet Mr. Shinkle is weighing whether to block certification at a board meeting scheduled for Monday, because of minor glitches that Mr. Trump and his allies have baselessly cast as evidence of widespread, election-invalidating fraud.