- A year ago, President Obama dropped plans to bomb Syria over chemical weapons
- Now Obama confronts the threat of ISIS jihadists that emerged from Syria
- Complex issues surround military action in Syria involving U.S. forces
- An election year at home also influences what happens over there
A year later, President Barack Obama will likely talk differently about Syria.
He addresses the nation Wednesday night to offer his strategy for "degrading and ultimately destroying" the ISIS jihadists who have swept across northern Iraq from Syria.
Exactly one year earlier -- on September 10, 2013 -- Obama also spoke to the nation from the White House to explain why he called off asking Congress to approve air strikes on Syria over its use of chemical weapons.
A lot has changed in the ensuing 12 months, particularly the rise of the Sunni extremists who call themselves the Islamic State and who seek dominance over a swath of the Middle East.
Here's a look at what Obama has learned about Syria in the past year:
1) Syrian President Bashar al-Assad isn't going anywhere
"I have resisted calls for military action, because we cannot resolve someone else's civil war through force, particularly after a decade of war in Iraq and Afghanistan," Obama said last year.
While he added that the United States had no interest in removing another dictator from power, he hoped the tide of the Syrian civil war would go against al-Assad to force him out.
Instead, the Syrian leader got help from Hezbollah in Lebanon and, indirectly, from ISIS fighters who formed out of al Qaeda affiliates to seize the advantage over what U.S. and allied officials call the moderate opposition in Syria.
That forced Obama to start providing military aid to opposition forces it considers legitimate and like-minded to Western desires for democratic governance in Syria.
2) Al Qaeda affiliates in Syria posed a broader threat
"It's true that some of Assad's opponents are extremists," Obama said of al Qaeda fighters who worked against the Syrian government.
He added that failure to respond militarily to al-Assad's use of chemical weapons would allow al Qaeda to "draw strength in a more chaotic Syria."
In the end, there was no U.S. military response after Britain's Parliament voted against taking part and Obama knew he would lack congressional approval.
While al-Assad gave up his known chemical weapon stockpiles, Obama's prediction came true as ISIS fighters comprising remnants of al Qaeda strengthened dramatically enough to rampage through northern Iraq.
3) The question of U.S. military action in Syria is complex
"I will not put American boots on the ground in Syria," Obama said a year ago. "I will not pursue an open-ended action like Iraq or Afghanistan. I will not pursue a prolonged air campaign like Libya or Kosovo."
Now he may propose some kind of air campaign against ISIS targets in Syria, and voices in Congress are calling for ground troops from a coalition military force -- but no Americans.
The issue raises major geopolitical questions involving who would benefit or be harmed by military strikes in Syria, as well as the legality of doing so without approval from al-Assad's government.
Attacking ISIS in Syria stands to benefit al-Assad by weakening what has become an internal enemy and allowing him to portray his country's civil war as a battle against terrorists opposed by the United States.
Strikes by a U.S.-backed coalition in Syria also would give Russia, al-Assad's main backer, fodder to justify its own border incursions in Ukraine.
4) Secure the coalition first
"I have, therefore, asked the leaders of Congress to postpone a vote to authorize the use of force while we pursue this diplomatic path," Obama said last year after Britain rejected joining a coalition to attack Syria over its chemical weapons.
This time, he is expected to detail support from global allies -- including some Middle Eastern countries -- in going after ISIS wherever the threat exists, possibly including Syria.
In addition, many in Congress question if Obama needs congressional approval to launch air strikes on ISIS in Syria, with several legislators saying Tuesday they doubted a vote would occur before November elections.
5) It's an election year
"America is not the world's policeman," Obama said last year. "Terrible things happen across the globe, and it is beyond our means to right every wrong."
But when "moderate effort and risk" by the United States can stop atrocities halfway around the world to make America safer, "I believe we should act," he added then. "That's what makes America different. That's what makes us exceptional. With humility, but with resolve, let us never lose sight of that essential truth."
Expect to hear the same thing Wednesday night, less than two months before the congressional elections, as the President straddles the political fault line between conservative calls for exerting military power and liberal opposition to a renewed war footing.
His goal is to satisfy moderates and independents crucial to Democratic hopes of holding on to control of the Senate while not angering the party's liberal base.