Bernie Sanders’ presidential campaign researched whether his rival Elizabeth Warren could simultaneously be vice president and Treasury secretary.

Sources on the Sanders campaign told the Intercept that the Vermont senator’s team looked into the matter, but there was not an official legal analysis by a campaign attorney.

Sanders was not involved in the inquiry, did not request it, and has not made final decisions on a potential running mate or Cabinet officials, his campaign said.

“No conversations are happening about any positions in a potential Sanders administration. Our campaign is focused on winning the nomination,” campaign manager Faiz Shakir said.

There is nothing in the Constitution that would prohibit a vice president from being Treasury secretary at the same time.

Warren, 70, and Sanders, 78, have been allies for more than a decade, but they clashed in the last week over Warren’s claim that Sanders told her a woman could not win the White House. Sanders has denied the accusation, which led to a heated exchange after the Democratic presidential debate in Iowa on Tuesday.

Warren, a Massachusetts senator, has been highly critical of Wall Street in the aftermath of the financial crisis. Sanders privately lobbied President Barack Obama to name Warren as the head of the Consumer Financial Protection Bureau after the crisis.