The debates are really important (just ask Kamala Harris and Julián Castro)

If the quarter had ended a week earlier, Ms. Harris’s fund-raising haul might have landed closer to the rest of the pack than to the four money leaders who raised at least $18 million. As it is, her $11.8 million put her in a unique place — $7 million-plus ahead of Senator Cory Booker yet $6 million behind Mr. Sanders.

But her campaign said she raised $3.2 million of her funds online in the days after the debate, when she distinguished herself with a riveting exchange over race with Mr. Biden. And records show she also received a jolt of larger contributors: in those same four days she took in about $950,000 in donations of $1,000 or more.

Translation: Without her breakout debate performance, Ms. Harris could well have been mired in the single digit club.

Julián Castro, the former housing secretary, also got a boost from the debates. His campaign said he raised $1.7 million in the first 85 or so days of the quarter and then $1.1 million following the debate. That surge allowed him to actually bank some money and avoid spending more than he raised . It also lifted him to the 130,000-donor threshold to qualify for the September debate (he now must also still meet the polling requirement).

The financial impact the first debates had on the Harris and Castro campaigns will only heighten the stakes of the next ones, which will be held in Detroit later this month.