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The Iranian saga has become a fixture in regional and international politics, with its multi-faceted, interconnected issues, challenges, trump cards and proxies. This has vexed regional and international players alike.

The disputed presidential elections in June sent ripples through the two competing camps — the reformists and the conservatives. As a result, the government has lost much of its legitimacy. Then came the suicide bombing last week in impoverished, majority-Sunni Sistan-Balochistan province, which has exposed the fault lines and ethnic strife within Iran's polity. This vulnerability could be exploited by its enemies to weaken Iran further and wreak havoc.

In the Middle East and beyond, Iran's fingerprints are ubiquitous as Tehran meddles in many...