(CNN) A New York appellate court ruled Thursday that a defamation lawsuit brought against President Donald Trump by a former "Apprentice" contestant can move forward.

A lawyer for Trump said he plans to appeal the decision.

Trump had appealed a lower court's ruling last year that allowed the case to proceed, arguing that the Constitution's Supremacy Clause bars a lawsuit against a sitting president in state court because it would interfere with his duties.

Mariann Wang, the lawyer for the plaintiff, Summer Zervos, argued that a president is not above the law and said the US Supreme Court's ruling in Clinton v. Jones backs up her argument that Trump can be sued in state court.

Judges in the appellate division of the first judicial department agreed with Zervos, saying the Supreme Court's decision "did not encroach upon the exercise of the executive powers of the President" and that the Supremacy Clause was "never intended to deprive a state court of its authority to decide cases and controversies under the state's constitution."

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