The Washington Post notes the move, and is puzzled by it.

While staging and refueling Tu-22s at Hamedan would make sense–Russia’s largest air base in Syria is too small to accommodate a detachment of the aircraft — the enduring presence of the Su-34s in Iran is a little more confounding.

A twin-seat, twin-engine multirole strike aircraft, the Su-34 has been flying from Russia’s Hmeimim airfield in Syria since 2015. The aircraft had only recently debuted in the Russian air force before its first combat sorties over Syria, prompting the Russian military to use the war-torn country as a proving ground for the aircraft’s capabilities.

Flying Su-34s into Syria from Hamedan would make little tactical sense, as they would need to hold more fuel than normal if they were taking off from within Syria. Michael Kofman, an analyst at the Center for Naval Analyses who focuses on Russian military operations, said there are two likely reasons for deploying Su-34s from Iran. The first would be to increase pressure on the United States to coordinate more closely with Russia; the second, to conduct air operations over Iraq.

Both of those ‘two likely reasons’ are about another, real agenda:  to provide defense in depth against a military option targeting Iran’s nuclear program.  As discussed here last week, Iran has attempted to use ballistic missiles and anti-aircraft missiles as a substitute for a modern air force.  However, its ballistic missiles are still primitive enough that they make sense as a weapon system only if Iran has access to nuclear warheads:  otherwise, they are too inaccurate and bear too small a payload to have military use.

Russia is able to provide Iran with the air cover that Iran cannot provide for itself, just as they are providing Iran with new high-quality anti-aircraft missiles.  Those missiles are a solid defense against almost all American strike aircraft, as well as all Israeli ones.  Only the F-22 and F-35, as well as the B-2 bomber, are thought stealthy enough to defeat the Russian S-300 system.

The Su-34 is not thought to be capable of air-to-air combat against the F-22 or its ilk, but it is a highly capable weapon against ground and naval targets.  Deployed American forces in Iraq are therefore under the threat of Russian airstrikes in the case of any move against Iran’s nuclear program.  No such move is coming soon, as the Obama administration is wedded to the fiction that the ‘Iran deal’ is some sort of solution to Iran’s nuclear ambitions.  However, the next President is likely to re-examine that question in a clearer light.

As a result, Russian moves now have the opportunity to work towards a more secure alliance with Iran over the next several months.  By January, when the next President takes office, it is likely that Russia will have solidified its control over Iranian airspace.  This serves Putin’s purposes better than sales of the most advanced anti-air weapons to Iran.  Far better for him that he should have control of the skies than that the mullahs should.