Definition:
Supporting a premise with the premise rather than a conclusion.
Example:
SUPREME COURT OF THE UNITED STATES – Nos. 06–1195 and 06–1196
JUSTICE SCALIA, with whom THE CHIEF JUSTICE, JUSTICE THOMAS, and JUSTICE ALITO join, dissenting (pdf, page 110ff):
America is at war with radical Islamists. The enemy
began by killing Americans and American allies abroad: ..
…
It has threatened further attacks against our homeland; one need only walk about buttressed and barricaded Washington, or board a plane anywhere in the country, to know that the threat is a serious one.
Shorter example:
Because the President says we have to fear, we do fear.
—
Why are such idiots allowed to judge?