Political scientists often like to rib pundits and the public for having a so-called “Green Lantern” view of the presidency, a theory defined by Dartmouth’s Brendan Nyhan as “the belief that the president can achieve any political or policy objective if only he tries hard enough or uses the right tactics.”

In reality, presidents operate under enormous constraints that often make them seem feckless in the face of intractable problems.

The news at the end of this week makes it clear that Biden has entered the “long slog” period of his first term. The bold ambitions of year one have been downsized. And even with more modest goals, unifying Democrats in Congress has become tougher — and winning over Republicans harder — than ever. Many problems, like inflation, don’t have readily available solutions. And even when Biden is able to act, like on immigration, his choices are politically perilous.

Biden’s sophomore slump truly set in this week…