According to the BBC, the "Mayor of Kabul", a.k.a Khamid Karzai, President of Afghanistan, has threatened Pakistan by warning that he would send "troops across the border" to "confront militants based in Pakistan" adding that when militants crossed over from Pakistan to kill Afghans and coalition troops, his nation had the right to retaliate in "self-defence".
There is, of course, a reason why the always elegant "Armani President" Karzai is referred to as "Mayor of Kabul" in Afghanistan: his influence does not extend beyond the Afghan capital (and even that, only courtesy of NATO firepower). All the real power in Afghanistan is either in the hands of the Tadjiks, Uzbeks and Hazara of the (former) Northern Alliance or the Taliban. Karzai has even less firepower than Maliki in Iraq (the latter can at least hope for some support from the Badr Corps). So when he threatens to send troops into Pakistan one can only either conclude that Karzai is talking about NATO forces or that the man has just gone totally insane.
Anyone doubting it should realize that even though Pakistan has a formidable military it never succeeded in controlling (nevermind defeating) the Islamists of Waziristan or anywhere else along the Afghan-Pakistan border.
Clearly, Karzai is humiliated and frustrated by the recent escape of over 1100 prisoners from a jail in southern Afghnanistan following a daring operation by Taliban forces. Still, the kind of utter nonsense he is spewing now is inexcusable for a person trying to impersonate a credible political leader. His delirious threats will only serve to confirm what many already knew: the Mayor of Kabul is little more than a buffoon.
UPDATE: also, check out the good commentary by Eric Margolis for the Toronto Sun.