As drug czar, Marino would oversee the Office of National Drug Control Policy, a branch of the White House that advises the president on drug policy issues. More than anything else, the office sets the tone of an administration's drug policy. Under President Barack Obama, for instance, the office quite publicly retired the phrase “war on drugs,” preferring rhetoric centered more on public health than criminal justice.
Whether that approach continues is something of an open question. Former drug czars from a more militant drug policy era have been publicly agitating to “bring back the war on drugs.” Trump's attorney general, Jeff Sessions, is moving to put criminal justice back at the forefront of drug policy.
Marino appears to be in that camp as well, but his views are unlikely to influence the administration's policy in the same ways Sessions's views do. That's because the drug czar's office has traditionally played a limited role in setting policy --instead, it coordinates drug control strategy and funding across the federal government.
Still, with the selection of Marino, another piece of Trump's drug control strategy falls into place. In Congress, Marino voted multiple times against a bipartisan measure to prevent the Justice Department from going after state-legal medical marijuana businesses. (The measure ultimately passed.)
