Obama's Plan: The Pros And Cons

President Obama's plan for an expansive air campaign in Iraq and Syria against the Islamic State appears to have broad support, but it will be a major undertaking that could still be playing out on the day he leaves office.

Here are the key points in Obama's plan, with a look at what it will take to make it succeed as well as the risks that could cause it to fail.

1. The president is opting for a broad, open-ended approach.

Throughout his presidency, Obama has consistently preferred to use American force in narrow, limited ways. His signature has been drone strikes targeting top militant leaders.

The new campaign is a sharp departure from his previous approach. While this mission also will depend on air power, the U.S. will pursue Islamic State extremists spread widely over two countries and will seek to drive them out of numerous cities and towns they control. All signs point to a large-scale effort that will last for years.

This means the president, and perhaps the next one, will need sustained U.S. public support for a campaign that's likely to be long and potentially messy.

"What Obama began last night will be left to another president to finish," writes David Rothkopf in Foreign Policy. "And it will continue to be a troubling constant in the life of a generation of Americans who have never known life without their countrymen engaged in military action in the Middle East."

2. The U.S. will not send in ground troops or engage in nation building.

When the president stressed that this will not be like the 2003 ground invasion in Iraq, he was seeking to reassure Americans that there won't be thousands of U.S. casualties.

But it also raises questions about whether the U.S. plan will be robust enough to eliminate the Islamic State threat. It took nearly nine years of war and well over 100,000 U.S. ground troops to beat back Iraqi insurgents during the 2003-2011 war.

No one is calling for a repeat of that model, but it means the U.S. will have to depend on the shaky Iraqi government and military.

Iraq has just formed a new government, but the former prime minister, Nouri al-Malaki, who has been blamed for the current mess, is still a vice president. There are many other familiar faces from the outgoing leadership, with some critics calling it more of a reshuffle than a fundamental change.

The Iraqi military dropped its weapons and fled in the face of an Islamic State offensive this summer. Now, two critically important security positions, the defense minister and the interior minister, have not been filled because there are no consensus candidates.

3. The U.S. will work closely with partners on the ground.

Just last month, Obama said the notion of arming the moderate Syrian rebels and expecting them to oust President Bashar Assad was a "fantasy."

In the interview with The New York Times, Obama said:

"This idea that we could provide some light arms or even more sophisticated arms to what was essentially an opposition made up of former doctors, farmers, pharmacists and so forth, and that they were going to be able to battle not only a well-armed state but also a well-armed state backed by Russia, backed by Iran, a battle-hardened Hezbollah, that was never in the cards."

The president on Wednesday night called on Congress to approve $500 million to train and arm these rebels and said they have an important role to play. He also ruled out cooperation with the Assad regime.

The moderate rebels of the Free Syria Army notched multiple successes in the early days of the Syrian war in 2011, but they have been a fading force on the battlefield and training them will be a time-consuming project.

4. The U.S. goal is to "degrade and ultimately destroy" the Islamic State.

U.S. has already had success with limited airstrikes in northern Iraq and can certainly weaken the militants further. But destroying the group will require some other party to move in and take over on the ground.

In Iraq, that could be the Iraqi government or the Kurdish peshmerga forces, both of whom the U.S. supports. But in Syria, Assad's regime or other radical Islamist factions might well retake areas where the Islamic State is forced out.

Eliminating the group entirely is a tall order, as the U.S. has learned in its battles against al-Qaida, the Taliban and other Islamist radicals.

The Islamic State shouldn't become an obsession that blinds the U.S. to other potential threats, writes Anthony Cordesman of the Center for Strategic and International Studies.

"The strategy the president announced also has a good chance of meeting half of his goals: seriously degrading the Islamic State," says Cordesman.

" 'Destroy,' however, is probably far too ambitious a goal," he adds. "A serious threat of violent jihadism and extremism is likely to endure for years to come, and re-emerge along with similar threats in an arc that reaches from Morocco to the Philippines and from sub-Saharan Africa to Russia and China."

Greg Myre is the international editor of NPR.org. Follow him @gregmyre1