(CNN) -- As they contemplate military action against Syria, one of many considerations members of Congress and Obama administration officials have to weigh is how a U.S. strike against the regime of Bashar al-Assad might effect the already complicated, even poisonous, state of Sunni-Shia relations in the region. Three of the leading Sunni states, Saudi Arabia, Turkey and the UAE, have already offered their military assets if a US strike happens. Last week, Iranian President Hassan Rouhani said that the Shia government of Iran and close Syrian ally Russia would work in "extensive cooperation" to protect Syria. An American-led war in Syria with the military backing of some powerful Sunni states against a de facto Shia alliance of Iran, Syria, Iraq and Lebanese Hezbollah would likely greatly exacerbate the already tense relations between Sunni and Shia across the region.
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Peter Bergen: Complicating the Syria picture is regionwide sectarian strife
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He says the historic Sunni-Shia split is a key dynamic and U.S. strike could worsen conflict
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Iraq's death toll from sectarian struggles has been increasing
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Bergen: Al Qaeda-affiliated groups will seek to take advantage
Syria
Syrian
Syria
Syria
Syria
Syria
The @placeholder regime is propped up with weapons and funds from Iran's Shia rulers and also benefits significantly from the support on the ground of battle-hardened fighters from Lebanese Hezbollah, an Iranian proxy.
Iranian
Iran
Iran
The Syrian regime is propped up with weapons and funds from @placeholder's Shia rulers and also benefits significantly from the support on the ground of battle-hardened fighters from Lebanese Hezbollah, an Iranian proxy.
Lebanese
The Syrian regime is propped up with weapons and funds from Iran's Shia rulers and also benefits significantly from the support on the ground of battle-hardened fighters from @placeholder Hezbollah, an Iranian proxy.
Hezbollah
The Syrian regime is propped up with weapons and funds from Iran's Shia rulers and also benefits significantly from the support on the ground of battle-hardened fighters from Lebanese @placeholder, an Iranian proxy.
Al Qaeda
Many of those deaths were the result of bombings claimed by the Sunni terrorist group @placeholder in Iraq and were directed at Shia targets.
Iraq
Iraq
Many of those deaths were the result of bombings claimed by the Sunni terrorist group al-Qaeda in @placeholder and were directed at Shia targets.
Sunni-Shia
Sunni
Shia
Sunni
Sunni
Sunni-Shia
Many of those deaths were the result of bombings claimed by the Sunni terrorist group al-Qaeda in Iraq and were directed at @placeholder targets.