No. 2 Iran

The United States and Iran have quietly - and sometimes vociferously - been somewhere between peace and war for nearly 30 years. Since the revolutionary regime's takeover of the American embassy in the fall of 1979, relations between the two nations have been at a cold standstill. Throughout the 1980s, the U.S. funded and aided the Arab sheikdoms surrounding the Islamic republic, and assisted Iraqi president Saddam Hussein in his long and bloody bid to seize the oil-rich, Arab province of Khuzestan from the Iranians.

While U.S. and Iran never officially engaged in direct warfare during that decade, the two countries did tangle in a quiet naval tit-for-tat in the spring of 1988 known as Operation Praying Mantis.

Not much has changed since then, and Iran's asymmetric naval capabilities have only adapted and matured since that brief engagement. If Iran were brazen and bold enough to grab control of the world's energy spigot, it would likely involve a naval engagement over the Strait of Hormuz.

The potential for conflict isn't excluded to the seas, either. With America's presence in Iraq appearing to be certain for at least the next three years, the risk of cross border engagement between Iranian proxies and U.S. forces will only become more likely. Tehran's proxy outfits - such as Hezbollah - are within striking distance of western embassies and offices all throughout the Middle East. Any action against the Iranians will likely involve reprisals elsewhere. An Obama response to Iranian mischief could require the safeguarding of Israel, the GCC states and all of the region's energy pipelines.

President-elect Obama has proposed unconditional negotiations between Tehran and Washington to resolve the abundant differences between both nations. But if the republic forces Obama's hand, how might he respond?