U.S. armed forces ready to support self-declared Venezuelan president Guaidó

President Trump has warned Venezuelan president Nicolás Maduro that a military action is an option in case he orders armed intimidation against self-declared Venezuelan ad interim president Gauidó and the Venezulan opposition. U.S. forces are preparing a possible intervention, starting namely from the Colombian soil, it seems. So, Maduro is sending his army, currently loyal to him, to that border.
To what extent would U.S. troops intervene in a military action against Venezuelan dictatorship? (Picture source: U.S. Army / Staff Sgt. Brandon Ames)