The law-firm battle for Supreme Court clerks was won this year by the Washington office of legal giant Latham & Watkins, but not without cost.

Each year there are up to 37 clerks available for hire, collectively, from the nine justices. Latham & Watkins beat out archrival Gibson, Dunn & Crutcher, getting five of those. Gibson Dunn got two. The rest scattered among law firms and academic positions.

Latham attorneys confirmed that the firm paid each clerk a $200,000 signing bonus, or a total of $1 million. The firm took one clerk each, sources say, from Justices Ginsburg, Alito, Breyer, Stevens, and Kennedy.

Latham’s appellate practice is headed by Maureen Mahoney, herself a former clerk to the late chief justice William Rehnquist. Mahoney was considered for the Supreme Court after the resignation of Sandra Day O’Connor.

Former solicitor general Ted Olson, who cochairs the Supreme Court practice at Gibson Dunn, says the $200,000 bonus “has become the benchmark”—what law firms will have to pay to attract a clerk. He points out that while Gibson Dunn hired only two clerks from this year’s class, four associates from the law firm will be going to the Supreme Court as clerks.

Olson is betting that when those associates leave the court next year, there is a good chance they will return to their former firm—a $200,000 bonus richer plus a nice salary. The justices themselves make $203,000 a year; their clerks average $60,000.

Why are Supreme Court clerks so valuable? Like LaVar Arrington delivering the Redskins playbook to rivals, each clerk provides insight into the thinking of a justice. That information, those who argue before the court say, is invaluable in crafting an argument that might persuade a swing justice to rule in a client’s favor.

Press coverage often focuses on court cases involving civil liberties. But many of the court’s decisions, as in a patent dispute between pharmaceutical giants argued by Latham lawyers this term, have billion-dollar ramifications for the winners and losers.

Thus, say attorneys, the million dollars spent by Latham is small change compared with what the firm can make by capturing a fifth vote in a 5–4 decision.