Stopping members of Congress from receiving their government employer contribution when they purchase health coverage on an Obamacare exchange was a hot topic last fall during the government shutdown. It was one of the many mechanisms that the GOP tried to use to extract a concession from Democrats on the law.

Though that ploy failed, Sen. Ron Johnson (R-WI) didn’t give up. He filed a lawsuit in federal court in January, attempting to undo the administrative rule allowing members and their office staff to keep their employer subsidy. The government’s lawyers retorted that Johnson had no standing to challenge, and part of their argument was that this is a benefit for Johnson. What harm could he claim?

A federal judge will hear oral arguments Monday on the standing question, according to USA Today, and he’ll consider a rebuttal from Johnson. Part of that rebuttal: Receiving this benefit under Obamacare could hurt Johnson when he runs for re-election in 2016.

“The ACA eliminated congressional subsidies so that Members of Congress and their staffs would experience the health care law’s highs and lows just like ordinary citizens,” a legal brief filed by Johnson’s lawyers in April says. “By circumventing this statutory mandate and restoring legislators’ favored status, the (rule) drives a wedge between Senator Johnson and his constituents and thus harms his personal reputation and electoral prospects.”

“This sort of personal political harm has long been enough for an individual legislator to challenge unlawful government action,” the brief concludes.

The administrative rule, issued by the Office of Personnel Management in August, clarified confusion about whether the federal government could keep providing insurance subsidies to lawmakers and staff after Obamacare required them to purchase coverage through the exchanges created by the law. OPM said in August that they could continue receiving the federal employer contribution.

His electoral prospects aren’t the entirety of Johnson’s argument that he has standing to challenge the OPM rule. The April brief also asserts that it forces him to participate in the rule’s “unlawful regime” and “take part in its law-breaking.”

But Johnson’s possibly diminished chances of re-election are still key to his case that the OPM rule causes him real personal harm and he therefore has the right to challenge it in court.

“By thrusting a favored status upon Senator Johnson, the OPM Rule drives a wedge between him and his constituents that causes him cognizable reputational and electoral injury,” the brief says. “Being forced to cooperate in unlawful conduct will certainly make a Senator unpopular with his constituents.”

Johnson Brief Obamacare Lawsuit