I'll have to disagree on one point: we don't have to match their technological capabilities in order to force them to the negotiating table - we just need a mechanism to knock them out of the sky. And that might be a whole lot easier than we think.
Yeah, lets play geopolitics (as some ufologists call it).
OK, so we knock them out of with strong radar beams. So what? That is exactly like bLack Africans shooting arrows at European colonists. Africans shot arrows, colonists responded with rifles, cannons and even Gatling guns.
They are here for some reason. If that reason is strong, they won't accept being interrupted by somebody much weaker than themselves. Europeans wanted industrial commodities from Africa, so that was a strong reason and arrows were not enough. If reason is weak, arrows would be a plenty, aliens would just leave and come back later, when we would have grown up a little more or when they can do some serious business with us, like trade, partnership in war etc.
Anyhow, the reason why they are here seems to be weak. They are obviously not extracting ore or not setting up some highly polluting industries they don't want at their own planet. It seems they are here mostly to do science, remotely possibly to genetically manipulate us into something they want, but that's a guess from a wild alley.
But than, what do we know. There is a remote possibility that we might as well be some kind of clones aliens developed for their own purposes. That would make their reason very strong. But that is unlikely, because apparently there is more than 50 species of aliens reported. They would start quarreling over to whose liking should clones be made. At any rate it's difficult to say.
The only real way to deal with aliens is to give them open access everywhere (because you can't stop them anyway) and work hard on developing commercial and cultural relationship. We can manufacture things for them and then buy from them their low tech stuff. We can offer them space-port facilities to replenish their ships and rest their crews etc. There is plenty mutually beneficial stuff we can do. Both our business, science and culture can enormously benefit from that exchange.
Let's say that in 20th century we developed more wealth than in all previous centuries combined multiplied by 10. If right today we established cooperative exchange with aliens, in the next 100 years, we would advance our wealth ten times faster than in 20th century. By the end of 21st century we would be 1,000 years ahead in wealth, science, culture etc. etc, not just 100. Some of us will be even sent as envoys and be able to pass on how other civilizations live so our soap operas and reality TV would improve imensly.
Defending some countrys territory is right down stupid animalism, when on other hand one has a whole universe to dig into.
For aliens we are their past. For us aliens are our future. Both sides can only benefit from each other.