A recent government study examined how test subjects' driving was affected by marijuana impairment.

Judge Andrew Napolitano appeared on “The Real Story with Gretchen Carlson” today to discuss if the results from the study could be used to design a new roadside sobriety test and what the legal ramifications might be.

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Judge Nap pointed out that any possible test must be based in due process, which means it must be approved by the courts. Additionally, the legislature must determine what number on the test constitutes impairment.

"The crime is not having cannabis in your blood," he clarified. "The crime is having the cannabis in your blood at such a level that your judgment is impaired while driving a car."

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Fox News' senior legal analyst likened this possible situation to the early days of drunk driving laws, with some innocent people being unfairly convicted and some guilty people getting away.

According to Judge Nap, the legislature will decide, based on science, a standard of impairment for all citizens, and then the courts will decide if that standard meets what the Constitution requires, which could involve many "fits and starts."

Watch the full discussion above, and check back on Fox News Insider daily for the latest from Judge Nap!

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