The GOP controls Congress, the White House and increased their hold in the states following the 2016 election, which puts the party in its strongest position since the Coolidge administration.
RealClearPolitics developed a scorecard that takes into account party control of the White House, Congress and state-level offices. Republican successes in the 2016 election have pushed that scorecard to its highest level since 1928.
However, the authors are careful to point out this does not portend continued Republican dominance ahead.
If you look over the broad sweep of history, this index has very little predictive power. The party that holds the presidency almost always loses strength, but the magnitude of that loss and how quickly it occurs is effectively random. Democrats should not be too discouraged by their present state of affairs. History teaches that it can be reversed, and rather quickly.