Treason is a crime of warfare, spying for the enemy and transmitting the information back to the partisan’s selected side.
From the US Constitution:
“Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the Testimony of two Witnesses to the same overt Act, or on Confession in open Court.”
The enemy is already within out gates. And the all-out war is imminent, the snipers are active and the ambushes frequent.
That's why the last person convicted of treason was some Japanese-American dude who was charged in the early 1950s after he had served in the Japanese Army during World War II.
Even Julius and Ethel Rosenberg weren't charged with treason. The U.S. was never at war with the Soviet Union. They were tried and convicted on espionage charges.
Paul Krugman is dumber than a reasonably intelligent sixth grader.