During the eight years that Joe Biden served as vice president to Barack Obama, he never cast a tiebreaking vote in the Senate. For eight years, Biden was just at the other end of Pennsylvania Avenue, should the Senate have needed his services. It never did.

This was a function of the composition of Congress, of course. Obama won in 2008 and came to Washington with a healthy Democratic majority in the Senate and his party controlling the House. There never was a point at which enough Democrats balked at a bill to require Biden to cast a vote. Then, in 2010, Democrats lost control of the House. Sure, there could have been something in the Senate that came down to a 50-50 split, but it didn’t happen.

Contrast that with Biden’s successors. Mike Pence was elected vice president in 2016 and, within the first 70 days, cast three such votes. His party had a four-vote advantage, meaning that losing two votes would require Pence to weigh in. So he did. Only Chester A. Arthur had broken more ties at that point in his term.

Then along came Kamala D. Harris. On Wednesday, as Bloomberg’s Greg Giroux pointed out, she cast her fourth tiebreaking vote as vice president. It’s a faster pace than any prior vice president.

It is a function of the current scenario on Capitol Hill. The Democratic caucus is 50 senators strong, meaning that any party line vote (that isn’t filibustered) might need Harris’s input. Three of her four votes to date were on the coronavirus reconciliation bill, including the final, non-filibusterable version. The fourth, Wednesday’s, was on an administration nomination, which is also protected from the filibuster.

If she maintains this rate, which she almost certainly won’t, Harris will have broken 32 ties by the end of the 117th Congress. That would be the most such vice-presidential tiebreaking votes in U.S. history, passing John C. Calhoun’s 31.

Again, that’s not likely. If Democrats hold the House in 2022 and maintain parity in the Senate, though? All bets are off. Pence’s Republican Party lost control of the House two years after he was elected vice president. Before the 116th Congress, he cast 13 tiebreaking votes. When Democrats took over the House, he didn’t cast another one.