Claims that the US helped with assassination attempts on Vladimir Putin are raising alarm about the risk of nuclear war — bad news for global stability.

• The US is alleged to have aided attempts to kill Putin, the leader of the country with the world's largest nuclear arsenal.
• Targeting a nuclear-armed head of state is framed as reckless, since it invites retaliation with no ceiling.
• Trump, as the only American able to order a nuclear strike, has been briefed on the weapons' power and has publicly and repeatedly warned they must never be used.
• Despite that, two years into his term the world is described as being on the brink of a nuclear exchange.

Outlook: Tensions between Washington and Moscow are expected to stay dangerously high with no clear path to de-escalation.