According to historical polling data (this data only reaches back to the 1930s, and only became really extensive in the 50s) the president’s party loses support during midterm elections. The factors that influence how severe the losses are tend to be the popularity of the president himself, the popularity of his party in Congress, the state of the economy (i.e. support falls if the economy is not in good shape), the state of the world (i.e. is there a war happening, and if so, is it going well?).
So this is what I know:
- Donald Trump is historically unpopular.
- The Republican majority in Congress is unpopular.
- The economy is currently in fairly good shape (low unemployment, low inflation, stock market humming along).
- We are at peace (mostly, we’re involved peripherally in wars in the Middle East and Afghanistan).
So this is what I don’t know:
Will Donald Trump’s historic unpopularity (and the unpopularity of the Republicans in Congress) outweigh the factors that would tend to support continued Republican governance?
There have been several articles talking about Democrats’ prospects this year, with Andrew Prokop providing a representative take.
1) The historical pattern strongly suggests that the president’s party is predisposed to face midterm difficulties.
2) Trump’s approval is remarkably low for a new president, and low approval is associated with poor midterm performance.
3) Democrats think their base is energized, which can contribute to recruitment of strong candidates, fundraising, and turnout.
There are complicating factors, however. The Senate only elects a third of its members every two years, and this year’s Senate map has far more Democrats defending seats in states that Donald Trump won in 2016 than there are Republicans that Hillary Clinton won in the same election. Democrats would have to sweep the vulnerable Republican Senate seats while holding all of theirs to regain control of the Senate.
Additionally, gerrymandering (the practice of drawing the shape of election districts to favor one party over another) by state legislatures which are majority Republican have made the map for the House of Representatives heavily Republican-leaning.
So will Democrats overcome their structural problems? Will Republicans weather their stormy president to fairer seas on an ocean of donations from grateful rich people? Stay tuned.