Was the Monroe Doctrine a policy of expansion or self defense?

I believe it was an effective self defense policy at the time. I've sometimes wondered what our Nation would have looked like in the 20th Century if we had maintained it. If we had stayed out of the Philipines, would we have stayed out of WWI? How would that have affected the direction of the world this century? I do believe that with globalization the Monroe Doctrine isn't maintainable today. Ron Paul and sons are wrong. We can't go back to isolationism.

Well, since we had a paltry army and navy at the time, it was largely ignored. The Brits went along with it and was its primary enforcer because it worked to keep France and Spain from getting back into it. The South American newly minted countries generally liked it but were also leery about US intentions over it. Probably some truth to if anybody is going to do expansion over here, it will be the US. One fallacy is people tend to look at whatever results there were and then ascribe the reason is to get to those results. Problem is most results are unintended consequences when it comes to major foreign policy. An exception would be the Marshall Plan, but that's a rare one.

A bit of both, we were flexing our political muscles as a regional power at the time.