Ukraine got a signed commitment in 1994 to ensure its security – but can the US and allies stop Putin’s aggression now?

In light of Russia’s annexation of Crimea and its current threat to Ukrainian sovereignty, it’s fair to ask: What is the significance now of the Budapest Memorandum?

5 things to know about why Russia might invade Ukraine – and why the US is involved

Russia has amassed an estimated 100,000 troops along its border with Ukraine over the past several months.