The substitution of the term "incursion" for "invasion" has a controversial history, one that goes generally forgotten or ignored by most present-day users. In what became known as the Incursion Address, Richard Nixon infamously announced, "This is not an invasion of Cambodia." That's his story, and he instructed his staff to stick with it. Four days later, students at Kent State, protesting the "incursion" labelled their own actions an incursion, and four of them were shot by National Guard troops.

Since that time, the term has been most commonly applied--as a strident voice points out, and as any NY Times reader or NPR listener can note--to Israeli actions in Lebanon and, more recently, the Occupied Territories. Hmm. Seems like pretty heavy baggage to lug into Baghdad with you.

If you've mastered the not-so-subtle nuances of "liberation vs. overthrow," take a look at "incursion vs. invasion." In a revealing but thoroughly unscientific snapshot of Google News (results 1-10, sorted by relevance), "incursion Baghdad" returns 9 US media sources and 1 UK paper quoting the Centcom spokesman. "Invasion Baghdad," on the other hand, brings up 8 foreign news sources (including Reuters UK) and two US stories: one quotes an American human shield, and one from the Times titled, "Food, Too, Can Be a Weapon of the War in Iraq".

Update: Check out Geoffrey Nunberg's article on "war-speak" in Sunday's NYT and Andy Bowers' pre-emptive war glossary on Slate.