scare the hell out of the country

[kjc0123]

What is the meaning of "scare the hell out of the country" in the following sentence? " The U.S. State Department devised a plan for U.S. assistance. But support for a new interventionist policy, Senate leaders such as Arthur Vandenberg told Truman, was only possible if he was willing to start "scaring the hell out of the country."

[Forelander]

He means to scare the country to a great degree.