"In the end, though, Mr McFate tends to overstate his case. Private armies may indeed play a role in failed and failing states, but it is unlikely that modern mercenaries will become more important than the standing armies of NATO or China soon."
And that should be obvious, too. Mercenaries aren't supported explicitly by any state, so they only fight where they're guaranteed to win, and they tend to be prosecuted for offenses official soldiers will not be prosecuted. They're not covered under most of the Geneva conventions, either.
Also, most of the people being labeled mercenaries these days aren't mercenaries. There's a big difference between people you hire to fight a battle and people you hire for base or convoy security.
"In the end, though, Mr McFate tends to overstate his case. Private armies may indeed play a role in failed and failing states, but it is unlikely that modern mercenaries will become more important than the standing armies of NATO or China soon."