The attacks by a roving band of assassins for which ISIS has claimed responsibility represent a deadly new escalation in the war on terror and raise the bar for all the leading presidential candidates -- none of whom has yet offered a cohesive, in-depth answer to the swift and deadly expansion of the group's international terrorism ambitions.
Less than 80 days before the first nominating votes are cast, the attacks could provide an especially strong challenge for GOP candidates like real estate mogul Donald Trump and former neurosurgeon Ben Carson and for Democrat Vermont Sen. Bernie Sanders. Such hopefuls have mostly struggled when confronted with national security questions or have argued that their lack of experience is actually an asset that appeals to voters fed up with career politicians.
But the latest manifestation of ISIS' widening reach, coming on the heels of the downing of a Russian airliner and a mass-casualty bombing in Lebanon for which the group is also suspected, could shift the relative importance of a president's experience, strategic vision and temperament in the minds of voters.
In the Republican race, especially, it's possible that the attacks could tilt the balance back towards more "establishment" candidates who tout administrative competence -- like former Florida Gov. Jeb Bush -- or who have put foreign policy expertise at the center of their campaigns, like Florida Sen. Marco Rubio.
While none of the candidates wants to be seen as politicizing such a terrible situation, their first comments hinted at a raging debate on the threat from ISIS that is now likely to become a major theme in the White House race.
"This is the war of our time, and we have to be serious in engaging and creating a strategy to confront it and take it out," Bush told radio host Hugh Hewitt.
"We cannot let those who seek to disrupt our way of life succeed," Rubio said in a statement.
Texas Sen. Ted Cruz added: "Between the downing of the Russian jet over Egypt and this massive coordinated attack on Paris, we are seeing an unmistakable escalation of ISIS' ambitions."
Trump sent his prayers on Twitter.
Front-running Democrat Hillary Clinton, meanwhile, said Americans must help "wage and win the struggle against terrorism and violent extremism."
But none of those statements suggested that the top 2016 candidates yet have a comprehensive strategy to resolve the crisis or are ready to mobilize U.S. public opinion to a more intense campaign against the terror group. In fact, they seemed to encapsulate the impotence of politicians who so far have only words to combat a burgeoning terror threat.
But the debate is likely to quickly intensify into a wider critique of existing U.S. policy on ISIS, offering an opening for a candidate who can frame the most compelling new strategy -- and offer a confident contrast with an administration that now appears to lack success in the fight against terrorism.
"I think that at least from my point of view, the vacuum of American leadership in this space has, in my judgment, been one of the challenges and provided some of the opportunities for ISIS to move much more aggressively," Tom Ridge, a Republican who served as the first U.S. secretary of homeland security, said on CNN's "Smerconish" Saturday.
"I do think Republican candidates, writ large, will be required to respond to this in a public way and those of us who are involved in the race and those of you who analyze it and comment on it will see what response makes the greatest sense."
Contenders, including those in Saturday night's Democratic debate in Iowa, must now confront a question likely playing out on the minds of many American voters. If a small group of terrorists, apparently schooled in carnage in the Syrian war, can turn the streets of France into an extension of the Middle East killing field, why can't it happen soon in New York or Chicago or Dallas?
"We have 250 fighters from the United States that have gone to fight in Syria as jihadists," Ed Royce, Republican chairman of the House Foreign Affairs committee said on CNN Friday night.
"We have a similar challenge here in the United States in terms of those who would try to find their way back and take the demands seriously that the ISIS leadership is making -- and that demand is to carry the attack to apostate civilian populations (to) attack soft targets, attack women and children, civilians," he said.
CBS, which is hosting Saturday's debate, informed the Democratic candidates that the format would be changed to incorporate questions about the Paris attacks at the the start, a shift met with some resistance from the Sanders campaign.
According to a source on a call between debate organizers and the campaigns, a Sanders aide "completely lost it" when informed of the change and argued that it shouldn't be allowed. After the rift was reported, Sanders campaign manager Jeff Weaver denied the dispute was resistance to discussing the attacks themselves, saying rather the conflict revolved around a push to shorten opening statements in order to accommodate for time to talk about the attacks.
"They wanted to make some last minute changes to the debate, we obviously wanted to keep the format to what had been agreed to, and I think people on our staff argued vigorously to that and were successful," Weaver said.
The dispute was first reported by Yahoo news
Blow to Obama
It is already clear that the horrific, multiple Paris killing sprees leave the foreign policy legacy of President Barack Obama in the Middle East looking even more threadbare.
It was a harsh political irony that the killings in France took place on the same day that an interview aired in which the President argued that his strategy had "contained" ISIS in Iraq and Syria.
Such comments, and the occasion when Obama referred to ISIS as a "JV team," now represent a significant vulnerability for Democrats who want to succeed him and an opportunity for Republicans portraying his tenure as commander-in-chief as feckless.
Clinton will get the chance at Saturday's debate to lay out a clear way forward on ISIS and make the case that her service in the Obama administration should be seen as an advantage, not a liability.
Despite Republican criticisms of her record as secretary of state, the escalating power of global terrorism could bolster Clinton's claims that her experience on the global stage has left her with a resume of statesmanship vitally needed in an age of crisis.
That narrative could at the same time further diminish her less experienced and trailing rivals, Sanders and former Maryland Gov. Martin O'Malley, who lack such international experience.
But any impulse from Clinton to call for tougher action against ISIS could also lead her onto dangerous political ground. She already appears to be much more hawkish than her party, which has little appetite for a new military commitment in the chaos of the Middle East.
Her calls for a no-fly zone in Syria to protect refugees have already been attacked by Sanders especially, who has used them to focus attention on her backing for the Iraq war in a 2002 Senate vote that helped derail her 2008 primary campaign.
An effort to lay out the more robust strategy against ISIS that the next president may eventually have to adopt would also put Clinton in the difficult position of criticizing Obama's current efforts at the same time that she is trying to reassemble the coalition of voters that helped the President win two terms.
And despite making clear that she would have taken a more proactive approach earlier in the Syrian civil war, her role as Obama's first-term secretary of state exposes her to GOP arguments that her presidency would simply represent an extension of the failed national security policies pursued by the current administration.
GOP calls for action
On the Republican side, Sen. Lindsey Graham has been a lonely voice calling for the deployment of American ground troops to fight ISIS in Syria.
But the back and forth on ISIS that has played out in the GOP primary race has most exposed the two front-running candidates Trump and Carson -- particularly in presidential debates.
Trump for instance, said this week that he would "bomb the s--- out of ISIS," and while he may be tapping into deep public anger at the group, his comments hardly hint at a thought-out military strategy, nor does his other recent claim that he knows more about ISIS than U.S. generals.
Carson, meanwhile, spent Thursday and Friday locked in a debate with the White House over his claim that Chinese forces, in contradiction of available U.S. intelligence, were in fact active in the Syrian war. It was a spat that seemed to reveal his idiosyncratic worldview and to suggest that he lacks a deeper grounding in national security policy. His campaign, though, later said Carson was referring to the presence of Chinese military equipment in the war-torn country.
The aftermath of the Paris attacks is likely not just to fuel Republican criticisms of Obama's record but to offer an opening for GOP candidates to distinguish themselves on national security.
One such candidate is Rubio -- who appears to have laid a shrewd bet years ago on carving out a foreign policy lane for himself in a potential presidential campaign.
In his statement on Friday night, Rubio offered the first hints of how his rhetoric on ISIS could evolve past his frequent and vehement critiques of Obama's leadership style.
"We cannot let those who seek to disrupt our way of life succeed," said Rubio, who serves on the Senate Foreign Relations Committee. "We must increase our efforts at home and abroad to improve our defenses, destroy terrorist networks and deprive them of the space from which to operate."
Ohio Gov. John Kasich spelled out an even clearer response at an event in Orlando Saturday.
"Today Nato should invoke article 5 of our NATO agreement, which basically says an attack on an ally is an attack on us and an attack on all of the Western world," he said. "We as Americans must assert leadership and we need to stand shoulder to shoulder with France and the French people."
Still, for the most part GOP candidates have yet to offer specifics on policy changes -- a vacuum they may now be forced to fill.
Some GOP candidates are already using the attacks to further their own political goals -- for instance, former Arkansas Gov. Mike Huckabee leveraged the news in Paris to bolster his calls for a toughened policy on immigration.
"These dogs are unleashed. The only thing we are going to ever do to stop them is to take aggressive actions," Huckabee said on CNN on Saturday. "If a left-wing, politically correct country like France will close its borders, it's time for us to put a moratorium on people coming here from countries where there are people with al Qaeda or ISIS ties."
Trump, for his part, went after gun control on Saturday.
"When you look at Paris -- you know the toughest gun laws in the world, Paris -- nobody had guns but the bad guys," Trump said at a rally in Texas. "You can say what you want, but if they had guns, if our people had guns, if they were allowed to carry ... it would've been a much, much different situation."
But the Paris attacks also expose Republicans to political vulnerabilities over ISIS. While the GOP base loves the kind of hawkish rhetoric that Rubio and others doled out at a presidential debate in Milwaukee this week, America remains weary of foreign wars, leaving little political room for new commitments by Republicans. And the legacy of President George W. Bush, whom many Democrats blame for ripping the lid off boiling sectarian strife in the Middle East with the invasion of Iraq, continues to haunt the GOP when it comes to national security policy.