And how do you ensure no one around you wants to take your land by force?

For example, keeping good relations with neighbours. Or unite with them, to occupy all island/continent, so there will be no neighbours left. Or having neighbours who are not obsessed with false "need more land to compensate for domestic fuckups" narrative.

Meanwhile, USA is a good example of a country without ability to defend its land. USA military just not suited for territory defence at all. If somebody decide to take over USA land, it will be a total disaster for the USA. US army don't have any clue how to fight on the ground, especially in defence. Nobody do that not because of military reasons, Nobody need that land. It will be a disaster to somehow develop and control it from distance. Every single "land conqueror" failed to do that - France,Britain,Spain. Russia was smarter - we just sold unneeded Alaska and part of California to infant USA, without any of that revolutions and clashes. In any case, all "conquered lands" quickly become independent from their respective metropolies.

Funny that at the same time USA military is fully mastered for the oversea land grab and control operфtions. Like example of Europeans didn't give any tip about how that will finally end.

"Need for more land" is in no way inevitable desire. It is just a ugly way to try to resolve own fuckups. It is not a common denominator or whatever "international rule".