As Trump builds the biggest military force since 2003 outside Iran, the U.S. impacts could swing from $2.50 to $5 gasoline.

President Trump has warned Iran that an attack would be "far worse" than the U.S. airstrikes that targeted its nuclear facilities last June.

As Trump builds the biggest military force since 2003 outside Iran, the U.S. impacts could swing from $2.50 to $5 gasoline.