[Leaning Right]

We should be doing something, had we acted in 1939 history would have been much different

Careful there. In 1914 World War I started because the Great Powers just had to do something. That war would have been avoided if the Great Powers would have just kept out the Austrian-Serbian crisis.

So is the current Russian-Ukrainian situation more like 1939 (action needed) or more like 1914 (stay out of it)? I vote for 1914.

[agere_contra]

WW1 started because Germany invaded Belgium on its way to France, and Austria invaded Serbia.

That's the reason WW1 was fought. There's nothing mysterious about it. Germany wanted a short, victorious war and - therefore - a pretext for war. That's why they seized upon an Archduke's assassination to give Serbia an impossible ultimatum. But anything would have done.