White House special assistant George David Banks speaks at an event organized by the Trump administration during November¡¯s United Nations Climate Change Conference in Bonn, Germany. (Lukas Schulze/Getty Images)

A?White House?climate adviser resigned Wednesday after failing to receive a permanent security clearance, becoming the latest member of the Trump administration to leave amid scrutiny of the background checks of presidential advisers.

George David Banks, who?was serving as a special assistant to the president for international energy and environmental policy, exited?after learning from White House lawyers that he would not be granted the permanent clearance, according to two officials who spoke on the condition of anonymity to discuss personnel matters.

Banks, who, like a collection of other White House officials, had been working on an interim security clearance, said in an email Wednesday that that his application was denied?after he admitted to smoking marijuana in 2013. ¡°It was an honor to serve the president at the White House, and I look forward to supporting the president in the future,¡± he said.

Politico first reported the specific reason for Banks¡¯ resignation.

The White House did not respond to a request for comment.

A lawyer by training, Banks served as an environmental official during the George W. Bush administration. He also worked on the staff of the Senate Environment and Public Works Committee under Sen. James M. Inhofe (R-Okla.), who repeatedly challenged the science of climate change during his time as chairman.

Banks later?worked at the American Council for Capital Formation, a nonprofit business group focused on economic policy. Along with the U.S. Chamber of Commerce, the group commissioned a report on the high costs of the Paris climate agreement that President Trump cited in deciding to withdraw from the international accord last year.

¡°While very conservative, [Banks] could articulate the real diplomatic, security and economic consequences for the U.S. of actions like leaving the Paris agreement,¡± said Paul Bledsoe, a former Clinton White House climate adviser. ¡°That voice will now be missing in the White House.¡±

In the fall, Banks represented the White House during a U.N. climate conference in Germany, and he didn¡¯t exactly get a warm reception. Demonstrators interrupted an event at which Banks and others had presented. It was titled ¡°The Role of Cleaner and More Efficient Fossil Fuels and Nuclear Power in Climate Mitigation.¡±

The protesters, who delayed the event for roughly seven minutes, sang a version of the country music song ¡°God Bless the U.S.A.,¡± with lyrics altered for an anti-coal message.

Banks took the protests in stride.

¡°Excellent singing,¡± he said. ¡°I think we should do karaoke after this.¡±

Chris Mooney contributed to this report.?

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