recent west coast missile defense tests shot down a missile over the pacific. but the system cannot be counted on to be 100% accurate. while this is just one intelligence assessment, fear is north korea is on track to solve the technical challenges sooner rather than later. >> the north koreans, if they proceed on their nuclear program, will figure out how to miniaturize the nuclear device. >> reporter: tonight north korea threatened guam while some lawmakers are slamming the president's comments. dianne feinstein recommending diplomacy. republican john mccain said he can't think of any other president who would have used that kind of rhetoric. >> whether president trump is prepared to back up his vow to meet with fire and fury, the statement reflects the narrow and risky options the united states has to try and halt north korea's nuclear advances. our national correspondent peter alexander takes a closer look. >> reporter: locked in an escalating standoff in a regime and its erratic dictator. tonight president trump is facing the first foreign policy showdown