Actually, for the US, you don't even have to hit anything.
A single nuclear explosion on the ground that hits an area of moderate importance would have tremendous geopolitical implications (to say the least), combined with probably a trillion dollar shock to the economy.
Three nuclear explosions somewhere 100 mi above the central US and West and East coasts would cause an EMP-triggered cascading failure of most consumer electrical devices for good, and most parts of the power infrastructure for months... if not years, considering the backlog of repair that would have to be coordinated and attempted without the use of power itself. In the meantime, countries not affected will use the effective absence of American involvement to promote their own agendas.
"Vaguely close, or in the right direction" is perfectly fine for nuclear effects.