It’s not just Missouri. Look at what happened in Alabama. I get the impression that the GOP in several states is really a foil for the Dem Party. It seems that they always throw the easy elections in order to elect vulnerable Democrats.
Another method they seem to be employing is to masquerade as Trump supporters. Never, ever believe a Democrat--NEVER. They are phonies. Vote straight Republican--always!!!
They deliberately throw elections if the Republican candidate is a reformer intent on slowing down or stopping the money spending party in Washington DC.
For years I have heard there was a "cabal", and for years I dismissed the idea as too ridiculous, but in the last three years I have come to see what I regard as pretty good evidence of a "cabal" that gets both parties colluding to keep the money spigot of Washington DC flowing to their businesses and their cronies.
Both the Democrats and the GOP are effectively agents of the donor class. Some people call these people the "globalists", as well as a few other names.
I see them as people who aren't loyal to any particular thing or entity, and who just want to make sure they are on the top of the power heap. For the sake of convenience we can call them "robber barons." :)