In Michigan’s August 6 Primary Election, you will have the opportunity to vote for the candidates that you want to be on the ballot in the November 5 General Election. Depending on where you live, you will get to vote for candidates for offices including U.S. Senator, U.S. Representative, State Representative, and various county offices. 

Ballots for the August 6 Primary Election have three columns: a Democratic Party section, a Republican Party section, and a nonpartisan section. All voters can fill out the nonpartisan section, but voters can only vote in one partisan section - either the Democratic Party section or Republican Party section. So, voters will vote in two columns (one partisan section and the nonpartisan section). If voters vote in all three columns, their ballots will not be counted. 

Note - You DON'T have to be a registered Democrat or Republican to vote as such.  You just can't crossover on the August ballot.