While there are no ironclad laws of politics, two tendencies in the United States -- midterm swings against the incumbent party (the "midterm blues") and the negative electoral effects of inflation and unemployment ("political business cycles") -- come pretty close. US President Joe Biden (whose approval rating has sunk for the past year) and the Democrats should not be surprised if they suffer a massive rout in the 2022 midterm elections.
But other long-accepted political truths have been discarded. For decades after World War II, two-party competition within a majoritarian system was thought to have a moderating effect. According to the celebrated "median voter theorem", originally proposed by the economist Duncan Black and then later by the political scientist Anthony Downs, if one party veered too far from the centre, it would pay for it at the polls.
Downs's observation was powerful, not just because of its theoretical elegance but also because it seemed to explain electoral politics for quite a while. The parties became so close on most issues as to entrench a moderate "liberal consensus". While some critics saw this as a "failure of democracy", many others regarded it as a feature of the system, not a bug.
