Why not hold the primaries the same day?

These days Democrats and Republicans agree on little.  In South Carolina, they can’t agree to hold their Presidential Preference primaries on the same day.  But if they did, Oconee election leaders say taxpayers’ money would be saved.  At least three members of the Oconee Registration and Election Commission would welcome same day voting for both parties.  Joy Scharich, director of county elections, agrees.  But, she says, it’s out of her hands.  Some election commissioners say, short of an agreement by the political parties, the only way to switch to same-day voting is for the state legislature to order it.