Which country has the best missile defense system?

Answer 1

Missile defense systems which can intercept launched missiles before they land come in two flavors:

In terms of long-range Anti-Ballistic Missile (ABM) systems which are employed in case of long-range nuclear warfare, the United States, Israel, and People's Republic of China have the most advanced technologies in the area.

In terms of regional missile defense, the United States, Russia, People's Republic of China, France, and India have such systems.

Notes:

Although the United Kingdom has both long-range and short-range missile defense systems, their usage and development rely heavily on the guidance of the United States. Similar cases include regional missile defense systems stationed in Japan nand the Republic of China (Taiwan).

Russia, being a large cross-continental country can relocate its anti-missile systems anywhere within the state territory, thus, eliminating the need of developing long-range missile defense.

European states, due to their lesser sizes (destroyed much too quickly in a nuclear war), proximity (easily reached by a short or medium-range missile from a neighbouring state) and protection from the United States (NATO and other defense treaties), do not have the immediate reason to develop long-range missile defense.