About those political fights ahead, Obama did not even pretend that they will take place among combatants who fundamentally respect the other side’s motives or basic decency. At repeated turns, he signaled the opposite.

Obama used the address to denounce opponents who “mistake absolutism for principle, or substitute spectacle for politics, or treat name-calling as reasoned debate.” His obstacles include people who ignorantly “still deny the overwhelming judgment of science” on global warming, believe the beneficiaries of Social Security and Medicare have turned America into a “nation of takers,” and would deny equal protection of voting laws to minorities.

There is no mystery where the absence of goodwill comes from: Obama believes he is matching the contempt conservatives have shown to him with contempt of his own.

But there is also no mistaking the significance of hurling these bolts from an inaugural stage, unprecedented in modern times. Until now, every inaugural address since George H.W. Bush’s in 1989, including Obama’s first in 2009, has included as a major theme an appeal for greater civility and mutual respect in Washington. The elder Bush said, “To my friends — and yes, I do mean friends — in the loyal opposition — and yes, I mean loyal: I put out my hand.” Obama’s speech will be recalled as a historical marker noting the decline of the once-common belief that internecine partisan wars in Washington were a short-term aberration that could be stilled through soothing rhetoric or symbolic outreach.

Obama deserves credit for abandoning pretense.