3. The executive strengthens yet further

The impeachment process appears to have continued a yearslong process of tilting the balance of power within Washington toward the executive branch and away from Congress. The president asserted his right to hold up, at least temporarily, legally appropriated foreign-aid funds for Ukraine, and then to resist all congressional attempts to subpoena witnesses and documents in the subsequent investigation.

Lawmakers from Mr. Trump’s party defended the chief executive’s right to resist congressional oversight, a precedent that won’t be forgotten. By arguing, as Sen. Lamar Alexander did in opposing calling witness to the Senate trial, that Mr. Trump’s actions in pressuring Ukraine were wrong but not impeachable, Republicans may have both clarified and pushed outward the line for any future impeachment effort.

Lawmakers from both parties have on multiple fronts—among them war powers, trade strategy and immigration policy—steadily ceded power to the president over the last two decades. Republican conservatives, though traditionally leery of too much centralized power anywhere in government, have gone along, and now may have accelerated the phenomenon with positions taken in the impeachment debate.