evidence: Prices for lumber, gas, wheat, coal and corn were sharply higher in April 2021, about three months after Joe Biden became president, than they were in April 2020. [...] For example, in the case of gasoline, experts said, tight supplies drove prices up from January, when Biden took office, to April (before a May hacker attack shut down a key pipeline). In general, a president has limited control over the weekly and monthly shifts in gasoline prices. [...] Blaming Biden for the inflation "seems an exaggeration at best," said Jeffrey Miron, a senior lecturer in economics at Harvard University and director of economics studies at the libertarian Cato Institute. "It likely reflects recovery from the recession/pandemic, concerns about monetary policy being too accommodating, as well as concerns that fiscal stimuli, including several adopted pre-Biden, are increasing aggregate demand and pushing up prices."