You have to start the negotiations before you slap more punitive sanctions on the Russians.

Negotiations don't start at a summit. The real negotiations take place between high level foreign ministry staff before the summit occurs. If you don't see that those negotiations are leading to real movement, you don't have a summit. The summit is mostly theater even in the best circumstances - but if you haven't worked out what the deal space is ahead of time, and confirmed that it's acceptable to you, then the summit is entirely theater.

This was a complete failure. They let an international pariah get red carpet treatment, even though it was completely foreseeable that he showed up to the summit with no intention to agreeing to anything other than his own wish-list terms. That's why you don't have the summit unless there's negotiations that demonstrate a willingness to actually reach an accommodation at the summit.