North and South Korea explained in four questions and answers.
Intentionally or not, Trump's approach to North Korea makes more sense than many people think.
Although North Korea's recent missile test is unlikely to have been an ICBM, they are likely to have a medium range missile that could hit South Korea in a few years.
Ultimately, the argument for Australia to acquire ballistic missile defence does not stack up.
North Korea does not yet have the capacity to launch a nuclear missile from a submarine. Its recent test, however, suggests it is making progress to a game-changing second-strike capability.