Iran and Syria: why the love?

Andrew links to this Slate article that attempts to explain an interesting piece of the Middle East puzzle: why are Syria and Iran so cozy with each other? This is something that every respectable armchair strategist should be able to talk about a little without sounding completely stupid. Here’s a sample:

But geopolitics has brought Iran and Syria together despite these many differences. In a strategic partnership that would have made Metternich proud, the two nations banded together against Saddam's Iraq, which both saw as an immediate threat to their security. Israel, too, provided a common foe. Iran's revolutionary ideology saw Israel as anathema; Syria also opposed the Jewish state, especially after its humiliating defeat in the 1967 war, since when it has strived to regain the Golan Heights. The United States is hostile to both regimes, producing further incentive to cooperate. Both countries worry that the chaos in Iraq will creep across their borders, but they're also keen for the United States to suffer a bloody nose to dampen its enthusiasm for regime change. Finally, both nations have few allies, making the other's support especially valuable.