Even with vaccine shortages and bottlenecks in delivery, the pace needed to meet the new administration’s goal — 1 million doses administered per day — was already achieved Friday and four other days of the previous eight, according to Washington Post data. The accelerating speed of the program undercuts assertions by some Biden advisers that they were left no plan by the Trump administration and suggests they need only to keep their feet on the pedal to clear the bar they set for themselves.

“I don’t think they would have set those goals if they had any concern about being able to meet them,” said Dan Sena, a Democratic strategist who helped chart the party’s takeover of the House majority in 2018. “I think Americans across the country are going to remember two things: the day they got vaccinated and day they went back to school or to work.”

To ensure success, top Biden aides have presented unflattering portraits of the state of the immunization campaign begun by their predecessors and promised to overhaul the use of the Defense Production Act, a Korean War-era law used to compel production of critical items.

But the Trump administration used the law 18 times in relation to vaccine production, according to current and former officials. Biden said this week that he was invoking it, which aides said meant directing agencies to explore prioritizing certain contracts. His plan envisions the possible use of this authority in a number of categories, but does not identify specific manufacturers or a timetable for what they would be able to produce, and at what cost to the rest of the supply chain.