The top Democrat on the Senate’s Middle East panel isn’t dropping the fight to force the Donald Trump administration to declassify the legal justification for the January drone strike that killed Iranian Maj. Gen. Qasem Soleimani in Iraq.

Sen. Chris Murphy, D-Conn., is appealing to an interagency panel within the federal government that’s tasked with reviewing declassification requests. Any member of the public may appeal to the Interagency Security Classification Appeals Panel (ISCAP) with a declassification request. But Murphy’s appeal marks the first time a lawmaker has turned to ISCAP to force the executive branch to declassify something.

“We’ve seen the Trump administration repeatedly classify information just because it is politically damaging to President Trump, and it’s up to Congress to stop it,” Murphy said in a statement. “The American people deserve to know why the Trump administration chose to kill Qasem Soleimani back in January, since this event had far-reaching consequences for US security. By hiding the legal rationale for this action, there can be no meaningful public debate about the wisdom of the strike.”

Why it matters:  The Trump administration claimed the Soleimani strike was legal as an act of imminent self-defense under Article II of the US Constitution as well as the 2002 military authorization to invade Iraq. After lawmakers had an opportunity to review the classified intelligence in January, Republicans largely sided with the president while Democrats maintained that Soleimani was not planning any imminent attacks on US interests, raising the prospect that the strike was illegal. Trump himself backed off the argument that Soleimani was planning an imminent attack when vetoing Congress’ Iran war powers resolution in May. Instead, Trump argued that the president’s Article II authorities allow him to take military action beyond instances of imminent self-defense.