The United States has experienced unusually low unemployment in the past two years: The unemployment rate has been 4% or lower in every month since December 2021. It hit its lowest level (3.4%) since 1954 in January and April 2023. It then rose to 3.9% in October before falling to 3.7% in November. Low unemployment has been highly beneficial for millions of workers. But can it last? When unemployment has been low in the past, it has remained low for varying time periods before giving way to a recession that caused unemployment to rise.Why Might Low Unemployment Be Followed by a Recession?The recent combination of very low unemployment and high inflation is consistent with the economic concept of a nonaccelerating inflation rate of unemployment (NAIRU) toward which the unemployment rate will naturally gravitate over the course of an expansion. Unemployment below the NAIRU could be a sign that the economy is overheating, further fueling inflation and therefore complicating the Federal Reserve’s efforts to restore low inflation. An overheating economy is, by definition, unsustainable, and the Fed is likely to respond to high inflation by raising interest rates, as it has done recently. A sharp rise in interest rates could itself cause a recession. Monetary tightening in such situations has historically resulted in recession more often than not. (For an in-depth discussion, see CRS In Focus IF12543, Has the Federal Reserve Achieved a Soft Landing in 2023?)