Will Republicans Move To The Middle To Keep The Majority?

The Republican Party wants to stay in power.
But, historically, the party in power gets crushed during the midterm elections.
One the one hand, the Democrats are damaging themselves.
Long time politicians are finding themselves in tough primaries.
California Democrats refused to endorse Senator Diane Feinstein.
The Democratic Party is moving further to the left.
Independent centrist voters are finding it hard to stay in the Democratic Party.