(CNN) Neil Young wants to become a US citizen and vote in the 2020 presidential election.

But the Canadian singer-songwriter says his citizenship application is being held up because he uses marijuana.

"When I recently applied for American citizenship, I passed the test. It was a conversation where I was asked many questions. I answered them truthfully and passed," Young said in a statement on his Neil Young Archives website. "Recently however, I have been told that I must do another test, due to my use of marijuana and how some people who smoke it have exhibited a problem."

According to guidance issued by US Citizenship and Immigration Services in April, an applicant who is found to have violated federal law on controlled substances, including marijuana, could be found to lack "good moral character" -- one of the general requirements for naturalization.

That policy applies regardless of state or local laws on marijuana use.

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