The first is the frequent tactic of insurgents of avoiding combat, dispersing from an area they had previously dominated, and waiting for US forces themselves to evacuate after a shadow "victory" before moving back. The implication is that US forces might need to maintain an almost permanent presence in areas they are able to secure. If it proves necessary to sustain troop levels at the new peak, this would carry major political consequences for Washington.

The second concern is another common insurgent pattern, of lying low and observing US operations, in order to develop new tactics as a result of the intelligence gathered.

A vivid current example was an extraordinary raid in Karbala on 20 January by insurgents who dressed in Iraqi military uniforms and drove black SUVs that were typical of those used by government forces. They looked and sounded so realistic that they were allowed through a security checkpoint into a headquarters area; there they engaged in a twenty-minute firefight, using percussion bombs, grenades and light weapons, and killed five US soldiers before escaping.

The third concern is that the most likely consequence of the US's "surge" policy is that insurgents disappear from the greater Baghdad area and concentrate in other towns and cities to the west and north. Since almost all the US troop reinforcements are heading for Baghdad, the already insecure environment in Anbar province (in particular) may become virtually a free-movement zone for insurgents.

If the insurgents respond with any or all of these tactics, a short-term lull in the levels of violence in Baghdad would not necessarily be a signal of the new policy's definitive success; only if it was to last for a year or more would it be significant.

Syria and Russia

The United States also faces overall strategic problems in its middle-east regional policy, which are highlighted by the Bush administration's response to (and effectively, quick dismissal of) the Iraq Study Group report. Most of the media attention surrounding this issue has focused on the White House's refusal to endorse the report's preference for a gradual troop withdrawal from Iraq; less prominent has been the rejection of the other main Baker recommendation, for active diplomatic engagement with Iran and Syria.

Indeed, as with the troop surge, the White House seems determined to do the opposite: it has directed increasingly vigorous rhetoric towards Damascus and Tehran, accused both regimes of collusion in the Iraqi insurgency, and backed its combative tone by deploying a second US carrier battle-group to the region.

The problem is that Syria and Iran do not constitute weak, isolated entities which are supine in face of Washington's wrath, but are being supplied with new armaments by Russia and China. Syria, for example, is seeking to replace its obsolete aircraft and acquire new anti-aircraft missiles and anti-tank weapons. Bashar al-Assad was accompanied by a powerful military delegation (including the head of the air force) on a visit to Moscow in mid-December 2006, and discussions there reportedly focused on buying new interceptors and upgrading older squadrons (see Riad Kahwaji & Nabi Abdullaev, "Syria Seeks Russian MiGs, Air Defence Missiles", Defense News, 8 January 2007 [subscription only]).

Such Russian sales to Syria, however, are far outstripped in significance by the provision of two other weapons systems: the long-range S-300 surface-to-air missile (which would pose a major problem for the Israeli air force), and the Iskander-E surface-to-surface ballistic missile (which, if deployed on the Golan Heights, could reach virtually all of Israel).

Intense opposition from Washington is likely to prevent Vladimir Putin agreeing to the Iskander-E proposal, making the S-300 deal the rather more likely one to go through. But even if both are aborted, the other arms transfers now being negotiated will allow Syria to modernise key parts of its armed forces.

Iran and China

China is providing another range of weapons systems in the region, this time to Iran. Over the last decade or so, the Chinese armaments industry has invested heavily in producing a wide range of anti-ship missiles, many of them designed to be fired from coastal batteries. The fact that the United States has by far the world's most powerful navy, and includes a fifth fleet dedicated almost entirely to ensuring a strong presence in the Persian Gulf and the Arabian Sea, makes any enhancement of Iran's anti-ship defences a major worry.

The current edition of a defence publication puts the matter starkly: "China has become an anti-ship missile powerhouse, developing a whole range of indigenous designs, establishing innovative uses of technology and strategic international partnerships" (see Robert Hewson, "Dragon's Teeth - Chinese missile raise their game", Jane's Navy International, January-February 2007).

China was, until quite recently, a regular purchaser of Russian weapons systems. Its primary consideration was the defence of the homeland from US naval forces, particularly the carrier battle-groups of the Pacific fleet. Today, it is concentrating on the development of an indigenous capacity, as well as an export market - while continuing to purchase some Russian systems where it feels there are gaps to fill.

It these arms sales lubricate the China-Russia strategic partnership, the partnership between China and Iran goes much deeper than weapons; as Navy International says, "the two nations have advanced from a straightforward seller/buyer relationship to one of technology transfer and weapons co-development".

This level of cooperation means that Iran can modify and otherwise develop Chinese designs specifically for conditions in the Persian Gulf and the northern Arabian Sea, and to meet the challenge posed by the ships of the US navy's fifth fleet.

It is worth remembering here that the US navy destroyed a substantial part of the Iranian navy in a series of operations at the end of the Iran-Iraq war in 1988. The Iranian military and political leadership still recalls these incidents, much as the US state department cannot forget the hostage crisis of 1979-80.

The belligerent statements on both sides of the Iran-United States divide, drawing on such historical memories and reinforced by current developments, highlights the risk of military confrontation. If it were to happen, the Iranian-Chinese military connection would come rapidly to the fore; the likely consequence would be an even greater Chinese involvement in the region. China's rapidly increasing dependency on imported oil is a factor in its own calculations no less than in those of the United States.

Measured in terms of months, what happens in Iraq is the main focus of western analysts. Measured in years, the Iran-China connection might be just as significant.