It will take years to know whether Mr. Biden’s initiative will have the lasting power of the New Deal or the Great Society, or whether it can “change the paradigm,” as he argued a few weeks ago.

Yet it is already clear it is based on the gamble that the country is ready to dispense with one of the main tenets of the Reagan revolution, and show that for some tasks the government can jump-start the economy more efficiently than market forces. Mr. Biden has also made a bet that the trauma of the coronavirus pandemic and the social and racial inequities it underscored have changed the political center of gravity for the nation.

Mr. Biden’s infrastructure plan fits with his declaration last week that “we’ve got to prove democracy works,” which was an acknowledgment that the Chinese government’s decision to underwrite “national champions” like the telecom giant Huawei and pour billions of dollars into key technologies like artificial intelligence is attracting imitators. Mr. Biden, his aides say, feels a burning sense of competition to prove that democratic capitalism can work.