The Senate moratorium, which will remain in place for two years, follows a similar move by the GOP-led House and a veto threat by President Obama in his State of the Union address last week. It’s the latest signal that Democrats are feeling political pressure on the issue of deficit reduction and are willing to consider measures that until recently they dismissed as posturing by their Republican adversaries.

Inouye, for one, has long argued that Congress has a constitutional imperative to direct spending as lawmakers deem necessary. Surrendering that power, the argument goes, will only strengthen the executive branch. Just last week, Senate Majority Leader Harry M. Reid (D-Nev.), who has delivered billions of dollars in perks to his home state, dismissed Obama’s veto threat as an “applause line” and urged him to “back off” the issue.

But Tuesday, Inouye said: “The handwriting is clearly on the wall. . . . Given the reality before us, it makes no sense to accept earmark requests that have no chance of being enacted into law.”