natural constraints. (This level of output corresponds to the Non-Accelerating Inflation Rate of Unemployment, NAIRU, or the "natural" rate of unemployment or the full-employment unemployment rate.) If GDP exceeds its potential (and unemployment is below the NAIRU), the theory says that inflation will accelerate as suppliers increase their prices and built-in inflation worsens. If GDP falls below its potential level (and unemployment is above the NAIRU), inflation will decelerate as suppliers attempt to fill excess capacity, cutting prices and undermining built-in inflation. However, one problem with this theory for policy-making purposes is that the exact level of potential output (and of the NAIRU) is generally unknown and tends to change over time. Inflation also seems to act in an asymmetric way, rising more quickly than it falls. It can change because of policy: for example, high unemployment under British Prime Minister Margaret Thatcher might have led to a rise in the NAIRU (and a fall in potential) because many of the unemployed found themselves as structurally unemployed, unable to find jobs that fit their skills. A rise in structural unemployment implies that a smaller percentage of the labor force can find jobs at the NAIRU, where the economy avoids crossing the threshold into the realm of accelerating inflation. Unemployment A connection between inflation and unemployment has been drawn since the emergence of large scale unemployment in the 19th century, and connections continue to be drawn today. However, the unemployment rate generally only affects inflation in the short-term but not the long-term. In the long term, the velocity of money is far more predictive of inflation than low unemployment. In Marxian economics, the unemployed serve as a reserve army of labor, which restrain wage inflation. In the 20th century, similar concepts in Keynesian economics include the NAIRU (Non-Accelerating Inflation Rate of Unemployment) and the Phillips curve. Profiteering under consolidation Keynesian price inelasticity can contribute to inflation when firms consolidate, tending to support monopoly or monopsony conditions anywhere along the supply chain for goods or services. When this occurs, firms can provide greater shareholder value by taking a larger proportion of profits than by investing in providing greater volumes of their outputs. Examples include the rise in gasoline and other fossil fuel prices in the first quarter of 2022. Shortly after initial energy price shocks caused by the 2022 Russian invasion of Ukraine subsided, oil companies found that supply chain constrictions, already