Are you suggesting Russia has assisted North Korea’s nuclear weapons development?
Absolutely, not only in terms of ICBM technology but also nuclear bomb technology, especially their miniaturization for use on ICBMs. DPRK do not have the skills or capacity to advance at this rate. There is a small 10-20 mile Russian DPRK common border which is used for the export of sanctioned goods where Russia is the biggest sanctions busting country, but last year Russia started a new ferry service between the nearest Russian and DPRK ports. Putin's judgement is that Little Rocket Man will only use the weapons against the USA or South Korea.
The proposed Kim and Trump summit will be in reality a Putin Officials, Trump summit with Kim as Putin's 'official' contact. The patsy in the room will be Putin's asset Trump where Putin must be very disappointed with his performance to date, but having him in the WH is better than a hostile POTUS, so Trump will come home with some sort of deal, but the important part will be what Trump has to do for Putin. What should never be forgotten is that there is a direct link between a Trump Tower server and a Russian Alpha Bank one. Some of its uses are in the public domain on its use in hacking computers containing state voting data being passed from the US to Moscow and social media messages targeted back in return. 5 eyes SIGINT is the best on the planet and there have been various hints that they know everything that the Trump crime clan have been up to. The difficulty of any intelligence data is that much is difficult to use in prosecutions without revealing sources, but it looks like Mueller has been targeting and turning key individuals by having this information, so he can then use their statements rather than intelligence sources, which is smart.