I'm wondering if it's a case of "idle hands are the devil's plaything", which would, as you've said, be easier for a larger country having a larger tax base and more cash-on-hand to spend on questionable pursuits.
I'm also permanently intrigued as to whether it's possible to succeed as a government without being evil. The good of the many at the expense of the few means being evil to 'the few'. Hard decisions have to be made, and when they're made they need to be committed too lest inviting insanity from constant second-guessing.
Tough gig either way, but the setting of behavioural precedents for "your people" should be of utmost consideration.
I think it can be done if the country is small enough and the government itself is small enough. Even if such states do end up meddling in the affairs of neighbors they won't be able to concentrate as much wealth into these actions as larger countries can.