Military pay increases are determined each year by an automatic statutory formula which Congress can choose to increase, decrease or leave as formulated by the law.
In fact, for 2018 Trump requested an amount below the automatic adjustment, but Congress overrode the president’s proposal, and Trump ultimately agreed to the increase, which again, is determined by federal law. Also, service members have received a pay raise every year for the last 35 years.
His supporters say he’s just imprecise in his wording, yet he’s made this claim more than once – just on May 9 and also back in March. Repeating a false statement after being told it is a false statement is actually called lying.