There’s no more mystery. Not for the West, anyway. Though the Egyptian-led investigation is far from over, leaks from the British, the U.S., and the Egyptian investigative team itself have put enough information in the public domain to be able to draw some pretty safe conclusions.

The black box from Russian Metrojet Flight 9268 shows there was an explosion onboard caused by a bomb (as opposed to a fuel line explosion organic to the plane). A review of U.S. and British SIGINT intercepts show the Islamic State discussing the attack prior to and after the downing of the plane. The Americans and British, in an extraordinary step, shared their intelligence intercepts with the Russians, who immediately halted all Russian flights to and from Egypt. This was a 180° turn from Russia’s stance the day before the Western intelligence was shared; Russia had insisted any suggestion the crash was attributable to terrorism was premature. The IS has now issued a third claim of responsibility for the bombing, asserting that they specifically targeted the Russian plane due to Russia’s involvement in the war in Syria.

How they did it is still up for speculation (the most likely scenario is that an airport worker at Egypt’s Sharm el Sheikh airport was compromised and put the bomb in the cargo hold), but there’s little doubt the Islamic State successfully committed the largest international terror attack since September 11, 2001.

The Russians aren’t happy about admitting it so quickly, though. The Kremlin’s propaganda machine has been focused on exhorting the modernity of the Russian military as it safely and surgically destroyed Islamic terrorists in Syria. Now it has to switch gears from glowing reports of military capability to spinning this new vulnerability into public support for a more protracted conflict, despite the threat to Russian citizens. Multiple Russian blogs are claiming the U.S., the Brits, or the Saudis (or some combination thereof), are responsible for the downing of the Metrojet flight. The Russians will likely encourage this kind of disinformation until the Kremlin can develop a cohesive anti-IS message that suits its goals.

Eventually, though, Russian President Vladimir Putin will have to respond to ISIS, just as the United States had no choice but to respond to al-Qaeda in Afghanistan after 9/11. Anti-Western rhetoric suits Moscow’s needs for the moment, but Putin certainly realizes that if the Islamic State can pull together an attack like this in a month (Russia began bombing in Syria in late-September), more attacks will follow. At some point it will be obvious to even media-isolated Russians it is the Islamic State, not the CIA, who is attacking Russians.

The rest of the world will, of course, focus on their own security in their own ways, but the Russians were specifically targeted, putting immense pressure on Russia’s strongman to act. Putin has invested enormous resources over decades to obliterate Islamic terrorists targeting Russia.

A great deal of Putin’s early political success was due to his response to Chechen Islamic terrorist attacks in the late ’90s and the 2000s as the Second Chechen War dragged on. Islamists bombed Russian apartment buildings and trains, attacked a theater, and took over 1000 people hostage at an elementary school in Beslan. At least 330 people died at Beslan, including 186 children.

Putin cast himself as the ultimate hard-liner against Islamic terrorism. He built his reputation as being ruthless and uncompromising. The brutal pacification of Chechnya while Putin was Russia’s prime minister and then president was supposed to be the ultimate deterrent against future attacks on Russia and Russian interests.

That deterrent no longer exists after the Islamic State blew up a plane full of Russian citizens.

Ignoring or minimally responding to the Flight 9268 bombing invites further attack, just as the United States’ refusal to acknowledge al-Qaeda as a military threat throughout the ’90s—from the bombing of the World Trade Center in ’93 to the attack on the USS Cole in 2000—invited 9/11. It also hurts Putin domestically. His people love him precisely because he’s a tough guy; ignoring or responding minimally to a new generation of Islamic terrorism will severely undermine his reputation in Russia. Russians want to see him respond violently to jihadis. The memories of suicide bombers in Moscow and of children massacred at Beslan are still fresh in the Russian public’s collective consciousness.

Putin knows inaction would be perceived as weakness at home, and weakness isn’t an option for a Russian leader. He knows he has to respond with overwhelming military force to satisfy both his constituents and the very real need to convincingly establish a deterrence policy.

And the reality is such a response is not necessarily a bad thing for his long-term plans for Russia’s role in the Middle East. Putin seems intent on displacing the U.S. as the indispensable power in the region. An expanded military role is an obvious step toward that objective. Russia is, of course, already bombing Syrian President Assad’s enemies in Syria at Assad’s invitation.

Over the next few weeks or possibly months, we will likely see an expansion of Russian operations into Iraq at the invitation of Baghdad and with the full approval of Tehran. And, while Russia is currently focused on attacking Syrian rebel strongholds on behalf of Assad, it will eventually have to take the fight to the Islamic State territory in Syria. Which means Russia will squeeze the US out of both Syrian and Iraqi skies, since US and Russian planes can’t/won’t fly in the same airspace.

As a de facto dictator Putin can escalate Russian involvement in the fight against the Islamic State as much as he wants. While a Chechen War-level invasion is unlikely in the near term, it, and any other degree of troop involvement, are possible. There is nothing off-limits for the Russians when it comes to dealing with Islamists targeting Russian civilians.

In 1985, when Vladimir Putin was a young KGB agent, Iranian-supported Lebanese Hezbollah militants kidnapped four Soviet diplomats. They executed one, and waited for the Soviets to accede to their demands (they wanted Moscow to pressure the Syrian government to stop pro-Syrian militiamen from shelling rival Muslim positions in the northern Lebanese city of Tripoli). The KGB found a relative of one of the LH commanders, castrated him, and sent LH his body parts—promising other LH family members were next. The Hezbollah militants immediately released the remaining Soviet diplomats.

There will be innumerable consequences from the determination that the Islamic State bombed Russian Metrojet 9268. Egypt’s tourism economy will take an extremely hard hit. Airport security will once again be ratcheted up, and travel anywhere there are active IS sympathizers and supporters will probably take a hit, from Kabul to Minneapolis.

But how Putin responds will shape the entire morass of violence in Syria and Iraq and beyond. If the past is precedent, the Middle East is about to get even bloodier.

(Featured image courtesy of businessinsider.com)