[There are lots angles to this, but they all follow the predictions made at at the very beginning of this imperial adventure, when Kurds were against it (back when they still had a choice), and this was one of the reasons: because they were afraid that Turkey and Iran, who had largely left them alone for a decade, would get scared by a condition of flux and start entering into their affairs in the north using proxies, seeking as always to divide them (PUK and KDP).]
[Historical footnote: As most everyone on this list knows, there was an uprising of Shias in the south that started the day Iraq surrended after the Kuwait war. The reason the US didn't aid them was because as soon as the rebellion took organized form, it turned out to be led not only by religious leaders (who supported the idea of setting up an Iranian style Shia-Islamic government in Iraq -- or just extending Iran's) but by actual troops from Iran who had crossed over the boarder.]
[Having this territory annexed de facto or de jure to Iran was the US's, and Saudi Arabia's, and Kuwait's, worst nightmare. It was to avoid precisely this outcomes that all three had backed Saddam in the first place so heavily during the Iran/Iraq war. To make matters worse, this territory also abuts on Al-Hasa, SA's eastern province, which contains its most valuable oil fields, as well as a discriminated-against majority Shia population.)
[Iran's intervention also contributed heavily to putting fire in the Iraqi troops who put down the revolt. The idea of suddenly losing a third of the country to Iran after having fought them off for 8 long years completely outraged the Revolutionary Guard.]
[Well, for the record: the guy that led those Iranian infiltrating forces during the Southern uprising was the same Ayatollah Hakim who appears in the report below as having now entered the North. Before and after being a leader in the revolt, he was and is the head of SCIRI (aka SAIRI), the Supreme Council (or Assembly) for Islamic Revolution in Iraq. Fwiw, he's also been one of the opposition forces we've been talking to all this time trying to get them all to put up a united front.]
Financial Times; Feb 19, 2003
FRONT PAGE - FIRST SECTION: US concern as Iranian-backed troops enter Iraq
By Najmeh Bozorgmehr in Tehran and Guy Dinmore in Washington
Iranian-backed Iraqi opposition forces have crossed into northern Iraq from Iran with the aim of securing the frontier in the event of war, according to senior Iranian officials.
The forces, numbering up to 5,000 troops, with some heavy equipment, are nominally under the command of Ayatollah Mohammad Baqir al-Hakim, a prominent Iraqi Shia Muslim opposition leader who has been based in Iran since 1980 and lives in Tehran.
A US State Department official said he was aware of reports that part of Ayatollah Hakim's Badr brigade had crossed into northern Iraq but declined further comment. Analysts close to the administration of President George W. Bush said the US was concerned about the intentions of this new element in an increasingly complicated patchwork of forces in northern Iraq.
Turkey has long had a limited military presence in northern Iraq, and US special forces began moving into the region several months ago. The Badr brigade has been trained and equipped by Iran's Revolutionary Guards and could be regarded as a proxy force of the Iranian government.
Iranian officials insist the force's role in the north is defensive but its presence will exacerbate the concerns of the US and especially the Arab world that military intervention in Iraq will lead to a permanent disintegration of the country. Through inserting a proxy force, Iran is underlining that it cannot be ignored in future discussions over Iraq's make-up.
Ayatollah Hakim's forces had previously been based in southern Iran, close to Iraq. Two months ago they began moving into the area of northern Iraq governed by the Patriotic Union of Kurdistan (PUK), one of two Kurdish parties that rule an area the size of Switzerland outside Baghdad's control.
A senior Iranian official said the presence of Ayatollah Hakim's troops was defensive and aimed at countering a possible attack on Iran by the People's Mujahideen Organisation (MKO), an Iranian opposition group based in Iraq and strongly supported by Saddam Hussein.