We are encouraged by the response of leaders and most Members of Congress to the Jan. 8 shooting of Rep. Gabrielle Giffords (D-Ariz.) and 19 others in Tucson, Ariz. We urgently hope they will live up to their vows to, in effect, detoxify American politics.

Not only would less vituperation and more civility improve the climate of political debate in Washington, it would also increase the possibility that the nation’s serious problems will be addressed constructively.

The proper tone was set by speeches in the House and by President Barack Obama’s oration in Arizona last week.

Minority Whip Steny Hoyer (D-Md.) suggested some self-editing is in order. “It is a time for us to reflect on the heightened anger being projected in our public debate and the daily denigration of those with whom we disagree and … on our own responsibility to temper our words and respect those with whom we disagree lest the failure to do so give incitement to the angriest and most unstable among us,” he said.

Speaker John Boehner (R-Ohio) declared that “we gather here without distinction of party. The needs of this institution have always risen above partisanship.”

The president, besides calling for less “politics and point-scoring and pettiness,” made these important points:

“Let us remember it is not because a simple lack of civility caused this tragedy — it did not — but rather because only a more civil and honest public discourse can help us face up to the challenges of our nation in a way that would make [the victims] proud.”

Congress and the executive branch are here to solve problems — to create “a more perfect Union” — and they are likely to perform their function much better through rational exchanges than bitter name-calling and partisan polarization.

It is not going to be easy either to maintain a calmer tone or to work constructively. Ideological differences are wide. Members tend to socialize largely with fellow partisans. Demonizing opponents is a proven fundraising technique. And we in the media cover conflict more avidly than consensus.

Some, in fact, disparage the whole idea of civility, as witness Rush Limbaugh’s statement Tuesday that the whole concept is an effort by liberals who, “like [Venezuelan dictator] Hugo Chavez, want to criminalize free speech.”

As a small step on the path to sustained constructive debate, we hope many Members will follow the suggestion of Sen. Mark Udall (D-Colo.) that Republicans and Democrats sit together during Obama’s State of the Union address next week.

A growing group of House Members and Senators have pledged to do so. It would be a good symbolic message to the country not to see half the House chamber cheering Obama and the other half sitting stonily.

But it’s what happens after the State of the Union that really counts. Obama and Republicans have to work together. During last year’s lame-duck session, they proved they can.

The problems the nation faces in the next two years — continued high unemployment, a massive federal debt, lagging education quality, income inequality — call for concerted action, not rancorous political gamesmanship.