Paris terror attacks make it clear that as Islamic State (IS) looses territory in Syria and Iraq, it would ratchet up its terrorist activities in Europe and rest of the world. The string of terrorist attacks in last few weeks - downing of a Russian airplane in Sinai, attacks in Lebanon and now mayhem in Paris - clearly establishes that IS has opted for organized terrorist activities as a war strategy.
Article 5 of NATO says, attack on one member country is to be considered as an attack on all. Friday's Paris terrorist attacks might not look like traditional armed forces aggression against France. But we cannot forget that IS claims to be Caliphat with sovereignty normally reserved for a state; unlike Al-Qeda, it commands a territory and has been deploying terrorism outside of its territory as a war strategy. Further, the danger of follow up attacks in UK and even possibly in USA is very much real. In other words, an enemy is actively engaged in war acts and intends to further damage Western population. No wonder French President is calling this as 'an act of war' and that means NATO and America cannot avoid a strong military response to these attacks.
American President George Bush, discredited the notion of 'to stop terrorism at home we have to fight bad guys in their homes'. But time has come for President Obama to overcome his political reluctance to get America more involved in Syria and Iraq. Sec. Kerry is trying to hash out a political transformation in Syria, but that is only one aspect. What is in the end needed is complete defeat and eradication of IS on the ground. Leaving that job to a singular credible force of Kurdish Peshmarga  or corrupt and deeply weakened Iraqi forces or rag tag multitude of rebel groups; that is unlikely to work. What we need is a quicker end of IS. Longer it takes to eradicate IS, more are Western countries exposed to terrorist attacks like Paris. Further, only depending on local forces to defeat IS would also result in splintering of Syrian Territory with the herculean task of unifying those factions after IS is defeated.
The scale of Paris attacks and specter of further such attacks would eventually move Public Opinion in Western Countries to commit forces on ground. It may not suit President Barack Obama's narrative that "he ended wars and brought American Troops back home"; but time has come for America to lead NATO in cleaning Syria and right the ship in Iraq. If that means sending American Troops back, so be the case. We all know defeating a rag-tag army of IS is not the hard part. Hard part, as Obama Administration is fond of saying, what happens afterwards. We all know Americans do not have much credibility as far as 'nation building' goes; failures in Iraq and Afghanistan are stark. President Obama is acutely aware of what happened in Libya when Americans only toppled Gaddafi but then let fester militants which ended in claiming American lives in Benghazi. America did not even bother to undertake any 'nation building' exercise there. That is where Sec. Kerry's UN brokered diplomatic initiatives come into the picture. While governance and political issues of Syria are sorted out through the UN brokered peace process; it is NATO which needs to lead the way to eradicate IS and establish durable peace on ground. 
Aside from softenning opposition of Americans and Western population in lights of Paris attacks, committing soldiers under NATO umbrella is going to be politically palatable for USA, France and many other countries. With UNSC backing obtained, NATO will be the legitimate force on ground to clean the stuff. Even Russia would favor working with NATO to defeat radicals rather than giving the sole operational space to USA. And with NATO, American military would still retain the operational freedom to pursue defeat of IS as how Pentagon deems it fit. As far as China goes, it understands that with it's globalizing economy and it's desire to play more constructive role at the world stage, it cannot afford to stay behind in blessing NATO operations by UNSC.
In the fight against IS, NATO does not need to shoulder all the responsibility. Continued partnership with regional countries like Saudi Arabia, Egypt, Jordan, Turkey and Gulf states will help spread the burden of defeating IS and rebuilding Syria there after. All these nations have a stake in Syrian peace. There will be thorny issues like what role Bashar Assad should play, how would Russia retain its military base in Latakia , how to undertake military action without getting Iran involved but at the same time keeping Iran at the negotiation table  and finally how to undertake military action without having a side war between Turkey and Kurds . Further, Paris attacks are bound to increase anti-immigration sentiments in Europe, especially immigration from Syria. Given that, quicker NATO frees Syria from IS, better are chances to stop displacement of Syrian people. Safe haven zone could be an intermediate step until whole of Syria stabilizes. But again, prerequisite for all that will be defeating IS in a military campaign and for that Obama Administration and European Governments for sure will have to adopt more strident and committed approach to fight IS. 
 Kurds will win battles where Kurdish population is present and Kurdish interests are involved. But naturally Kurds are going to be squeamish and definitely less successful, especially a day after IS defeat, in areas like Raqqa where Arab Sunni's are present. This sectarian dimension naturally limits where Kurds can win against IS and where they can sustain those gains.
 President Barack Obama will be able to run with the narrative that 'let local forces' sort out the mess in these distant places and it is prudent for America to stay away from these complicated situations; only so far. As more terror attacks like Paris start, that 'narrative' is not going to work. George Bush lost credibility because he picked wrong enemy in Saddam Hussain while the enemy IS in this case is nakedly open and identifiable. As IS sponsored terrorism piles, President Obama cannot hide behind difficulties of 'what happens afterwards' i.e. 'nation building' to avoid undertaking necessary military intervention in Syria.
 Syrian President Bashar Assad is the root reason why we have this chaos in Syria spilling all over the world. He slaughters his own people who started a peaceful resistance. There is no possibility whatsoever that larger Syrian population would accept him as the leader of all of Syria. However, Russian President Putin backs him because Russia sees him as the care taker of Russian interests in Latakia. What President Putin is not sure is when post-Assad government installs in Syria, whether it would back Russian Navy in Latakia or not. Having backed Assad so far, and having intervened Syrian Civil War on behalf of Assad; it is very unlikely that post-Assad political powers in Syria would allow Russian Navy presence in Syria. But given the composition of Syria along sectarian lines, Assad's Alawites concentrated in and around Latakai; there will have to be acceptance by rebels in Syria that security of Alawite population needs to be equally ensured as well. If such a security guarantee involves Russian involvement, even military presence on Syrian coasts; then so be the case. USA, UN and rebels all will have to accommodate such a Russian involvement in that case.
 Iranians are involved in Syrian internal matters to defeat IS and protect Shiite population. Iranian forces worked along with Shiite forces of Iraq to defeat IS. As Iranian entanglement increased in Syria, Iranian military officers and soldiers died in Syria as well. In a sense Iranian blood is shed to protect Assad. Given recent suicide attacks against Hezbollah and their Shiite supporters in Lebanon; Iran will feel compelled to remain involved. But if NATO and Americans commit soldiers in Syria, Iranian involvement needs to be curtailed. Iran would not accept that. But by retaining Iranian presence at the negotiation table - UN led political transition - Western countries can allow Iran to have some say. The trick is to convince Iran that in order to have an influence to shape Syrian future, it is not necessary to get involved militarily in Syria. Again Obama Administration needs to stop seeing Iranian involvement as the 'outsourcing of dirty work of defeating IS'; time of any such free ride is over.
 Turkish President Erdogan started the war against Kurds to win his parliamentary elections. Now that he has achieved his objective, America needs to stop Erdogan from using the pretext of Syrian civil war to wage another parallel war against Kurds. A complicated issue here is to make Erdogan realize that his objective of removal of Assad and a peaceful Syria with stanched immigrant flow into Turkey, all that will realize only when he restrains his hyper sensitive aggregation against Kurds.
 Paris attacks have essentially created a political space for President Obama to maneuver and commit greater American military involvement. His traditional Republican opponents will criticize him for being so late in addressing the challenge of IS. But 'better late than no show'. Upstart Republican Presidential candidates like Trump, Fiorina, Carson or isolationists like Ron Paul will be completely pushed aside by people's anxiety about organized terrorist attacks and people's expectation to act. Same will be the fate of Bernie Sander's style isolationism advocated by American Left. Hillary Clinton will be deft enough to build on her hawkish policy prescriptions to exploit the political opportunity which will be opened here for her. In a sense, President Obama will not find any better successor than Hillary Clinton in carrying forward American policy of greater involvement in Syrian. If all this means Republican Party is shut out completely from White House the third time in row due to seceding foreign policy advantage to Hilary; that is just a collateral damage worth ignoring.