Massachusetts Gov. Charlie Baker led a dozen governors in signing a letter urging Congress to lift the federal ban on marijuana and allow states to craft their own marijuana laws.Massachusetts legalized medical marijuana in 2012 and recreational marijuana in 2016. But the continuing federal ban leads to difficulties in the industry. Marijuana businesses cannot access loan and banking services that are accessible to other companies. It is harder to conduct scientific research on marijuana, and using the drug can jeopardize a college student’s financial aid.