Trump appointed his vice president to lead a "war on fraud" as he railed against alleged abuses of government benefits in Democratic-controlled states -- particularly Minnesota.
The US president charged in his State of the Union address that similar problems are taking place elsewhere, in states like California, Massachusetts and Maine.
"I am officially announcing the war on fraud, to be led by our great Vice President JD Vance," Trump said.
He claimed that if his administration could "find enough of that fraud, we will have a balanced budget overnight."
US President Donald Trump delivered the longest-ever State of the Union address on Tuesday, beating Bill Clinton's 2000 record of one hour and 20 minutes.
Republican Trump also smashed his own 1 hour and 40 minute record for a presidential speech to Congress, which he set last March in an annual address that was not technically a State of the Union.