Story highlights

• Peter Bergen: Jihadi John may have been killed in drone strike. That and Kurds seizure of Sinjar would be two tactical victories against ISIS
• He says gains, like slowing of 'foreign fighter' flow may mean 'the end of the beginning,' but it will be years to rout ISIS from much of Iraq

Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of "Manhunt: The Ten-Year Search for bin Laden -- From 9/11 to Abbottabad."

(CNN)In a speech in 1942, Winston Churchill said that a recent British victory against the Nazis in North Africa was "not even the beginning of the end, but it is, perhaps, the end of the beginning."

But there is no evidence suggesting that Jihadi John was an important spiritual leader of the group, as ISIS leader Abu Bakr al-Baghdadi is, nor is there any evidence that he played any kind of important military role for ISIS. Therefore, while Jihadi John's death would surely be a psychological victory in the war against ISIS, it is nothing more than that. The second tactical victory against ISIS over the past 24 hours will likely have far greater significance: It is the seizure of the town of Sinjar in Iraq by Kurdish forces. Sinjar sits along the road that connects Raqqa with ISIS' de facto capital in Iraq, the city of Mosul. The seizure of Sinjar will help put pressure on ISIS in both Mosul and Raqqa, as ISIS forces in these cities can no longer easily reinforce each other. Neither of these tactical victories are, however, strategic victories such as would be the capture of Raqqa or of Mosul or of the other significant Iraqi city held by ISIS, Ramadi. President Obama told ABC News on Friday that ISIS is "contained" and has not gained ground in Iraq or Syria, and there has also been progress in stemming the flow of foreign recruits trying to join the group. The President acknowledged that the coalition hasn't been able to "completely decapitate" ISIS' leadership. Does this mean that the coalition against ISIS is locked in a stalemate with the terrorist army, or has the momentum of the military campaign started to shift against ISIS? In September, Gen. Martin Dempsey, the outgoing chairman of the Joint Chiefs of Staff, said that the war against ISIS was "tactically stalemated." Indeed, during this past year ISIS has retreated from the town of Kobani on the Syrian-Turkish border and it also lost the Iraqi city of Tikrit. Despite these losses, ISIS during the same time period captured the city of Ramadi in western Iraq as well as the town of Palmyra in Syria. As the president noted, the stream of "foreign fighters" from around the Muslim world, which has consistently replenished ISIS' ranks, has been reduced. An estimated 30,000 foreign fighter volunteers have joined ISIS, averaging about a 1,000 month. But two factors are now affecting that flow. The first is that ISIS has lost significant territory in northern Syria, so that it now controls only some 60 miles of the Syrian-Turkish border, down from the 600 miles of border that the group once controlled, according to a senior administration official. Coalition forces' gains against ISIS have significantly hurt the ability of the group to move foreign fighters through Turkey into Syria, which is how most foreign fighters travel to reach the group. Turkey, which had long been criticized by Western countries for allowing foreign fighters to move through its territory on their way to Syria, has started to clamp down on that traffic into Syria. Those efforts by the Turks are paying off, according to ISIS itself. In early 2015, ISIS posted advice in one of its English language online publications to would-be foreign fighters saying, "It is important to know that the Turkish intelligence agencies are in no way friends of the Islamic State [ISIS]." Also, some 40 countries have also introduced new laws to prevent the recruitment of fighters to ISIS or have launched criminal investigations of militants who have joined the group. These developments are surely having some effect on ISIS' ability to recruit foreign fighters to its ranks. If confirmed, the death of the most infamous of them, Jihadi John, and the seizure of Sinjar may well be "the end of the beginning," but the campaign to extirpate ISIS from Raqqa and Mosul, Iraq's second-largest city, as well as much of Anbar province--which makes up about a third of the land mass of Iraq--will still likely take many years.