The second part of the statement is part and parcel of the first for Paul. It's not like extended military engagements don't require spending of taxpayer money or result in smaller government. Debt is debt regardless of whether it's spent on interminable welfare programs or interminable wars.
There is some truth to that, but Ron Paul seems to take it too far, into an unreality in which we never face problems which are not as clear-cut as he might like them to be.
I have some sympathy for being much more isolationist than we have been, but recognize that international trade bumps into that a bit. For instance, we could not tolerate Saddam invading Kuwait for good reason. He was attacking our trade partner, and therefore our trade.
There are certainly wars we have fought, however, that had no national interest implications of any significance: Somalia, Bosnia, Kosovo, etc.