What do drones have to do with the Intermediate-Range Nuclear Forces or INF Treaty that was negotiated between the US President Reagan and the Soviet General Secretary Gorbachev back in 1987? Surprisingly, a great deal. Australian ABC News says that Russian President Putin has claimed that his country possesses a "nuclear-powered cruise missile." Not really clear how that would work, but a cruise missile (Which we often refer to nowadays as a drone) that's tipped with a nuclear warhead is entirely plausible.
As far as a missile defense system is concerned, there is a very big difference between a regular missile and a drone, even if they have about the same range (and thus both fall under INF Treaty standards). A regular missile travels to its target in an arc. There is a time during its travel when it's easy to spot and is just surrounded by empty air. A drone travels along whatever path its remote pilot sends it on. A drone is much, much more difficult to intercept or to even detect. Congress has concluded consistently since 2014 that Russia has been testing an intermediate-range drone (That is, its range is from 500 to 5500 miles). Suspicions began as early as 2008. Russia has steadfastly denied that any testing has taken place. The US has specified the particular model that it claims Russia is testing (Novator 9M729, an extended-range version of the Iskander K). It's not clearly established that Russia has violated the INF Treaty, let alone that they've actually placed a nuclear warhead onto a drone. It's far from clear that withdrawing from the INF Treaty is the best answer, but no one appears to have a better idea.
The reason that US National Security Adviser John Bolton gave for the US to want to pull out of the INF Treaty was so incredibly stupid, it's hard to think that's the real reason:
Bolton also said the treaty was a "Cold War bilateral agreement" but we are now in a "multi-polar world" and we need to reflect this "new reality."Which makes zero sense. What appears to make more sense is that the plan is to introduce friction between Russia and China. "It is important to reiterate that China and Russia have a comprehensive strategic partnership, but not a military alliance. Notably, both sides have also repeatedly stressed the non-alliance aspect of their military ties in the past."