Thanos Thanos:
Being caught working for Russian intelligence should be an automatic death sentence.
Why? Everyone spies on everyone else. That's the way of the world. No one is surprised that they are being spied on, because they do it themselves, so no one is shocked when they catch a spy.
The only bad thing is getting caught. That means you weren't very good and you made a mistake. That shouldn't be punishable by death, only punishable by embarrassment and being used as currency to be exchanged for other spies who were equally sloppy.
If we shot Russian spies, then all that will engender is they'll shoot ours instead of using them to embarrass us.