An overwhelming bipartisan majority of the Senate voted 90-8 today to confirm former Army Secretary Mark Esper as President Donald Trump’s new defense secretary. The outliers? Mostly Democrats running to oust Trump from the White House.

Democratic Sens. Kirsten Gillibrand of New York, Elizabeth Warren of Massachusetts, Cory Booker of New Jersey, Amy Klobuchar of Minnesota and Kamala Harris of California all voted against the nomination. Michael Bennett of Colorado was the only Democratic presidential candidate in the Senate to vote for Esper while Sen. Bernie Sanders, I-Vt., didn’t vote.

Why it matters: Although numerous Democrats have voiced concern about the lack of Senate-confirmed leadership at the Defense Department as tensions with Iran continue to mount, most presidential candidates in Congress offered myriad reasons for voting against Esper’s nomination — some of which have direct implications on US policy in the Middle East.

Separation of powers: Shortly after the vote, Gillibrand tweeted that she voted against Esper in part because of the Trump administration’s stance on the use existing legal authorities to use military force in the region — formally known as an authorization for the use of military force (AUMF).