For Harris, the Senate Was a Springboard and a Chance to Form Alliances

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Vice President Kamala Harris spent four years as one of 100 members of the Senate, forging relationships that are likely to be crucial should she win the presidency in November. But her most significant votes may have come after she left Capitol Hill for the White House.

As vice president, Ms. Harris is also the president of the closely divided Senate, where she has cast deciding votes on some of the biggest legislative achievements of the Biden era. She helped push through the $1.9 trillion Covid relief package and the landmark Inflation Reduction Act — both over the solid and strenuous opposition of Republicans. She also cleared the way for numerous confirmations of executive branch officials and federal judges to lifetime terms, amassing a record number of tiebreaking votes by a vice president.

“I can’t tell you how many times she rode to our rescue,” said Senator Richard J. Durbin, Democrat of Illinois, who as chairman of the Judiciary Committee worked with Ms. Harris on the often partisan panel.

Democrats gathered in Chicago for their party convention have celebrated her tiebreaking record, which is already the subject of Republican attacks, playing videos showing her bringing down the gavel on those big bills.

Like Barack Obama before her, Ms. Harris never became a creature of the Senate; she used her relatively short time there as a steppingstone to higher office and did not build the kind of reputation and record that come from investing decades in the institution. But in her role as a senator and then vice president, Ms. Harris did get a feel for the rhythms and vagaries of a legislative body that would be pivotal to her success should she become