As Gabriel Weimann, a professor of communication at Haifa University in Israel who studies terrorists’ Internet use, points out, the Al Qaeda core continues to rely heavily on “older” Internet platforms like websites and online forums rather than more modern social-media platforms frequented by young people (Twitter, Facebook, Instagram, etc.). This makes sense: on September 11, 2001, at the height of Al Qaeda’s power and influence, the very first iPod had yet to be released, laptops with built-in Wi-Fi were the hot new technology and Myspace wouldn’t even be launched for another two years—let alone Facebook, Twitter or YouTube.

The Islamic State, on the other hand, came of age in the world of smart phones, hashtags and viral videos, and its public-relations methods reflect this: the group issues propaganda in multiple languages across multiple social-media platforms, even hijacking hashtags like “#WorldCup2014” to get its message out. Some of its propaganda comes from the top, but much is generated from below, enabling it to crowdsource jihad—recruiters even encourage incoming fighters to bring their smart phones with them so they can share their exploits on the battlefield on Twitter and Instagram. Indeed, Islamic State supporters reportedly were behind the January hacking of the U.S. Central Command Twitter feed.

Some of Al Qaeda’s affiliates—particularly Al Qaeda in the Arabian Peninsula (AQAP), the group behind the online magazine Inspire—have updated their online propaganda efforts to keep up with the times. But the Al Qaeda core still mostly produces variants of the same tired old content it has been putting out since 2001—long videos featuring senior Al Qaeda ideologues pontificating about various aspects of jihad and quoting extensively from the Koran. Compare this to the video released by the Islamic State titled Flames of War, which features rousing music; dramatic explosions; clips of Barack Obama and George W. Bush overlaid with CGI flames; footage of jihadists firing RPGs in the midst of battle; graphic, blood-soaked images of dead enemies; and a voice-over (in English, of course, with Arabic subtitles) detailing the glorious rise of the Islamic State. Which do you think is more likely to attract the attention of an eighteen-year-old dreaming of adventure and glory?

TRADITIONAL JIHADIST ideologues oppose the Islamic State. Even the extremely influential Abu Muhammad al-Maqdisi, who mentored Zarqawi when the two were together in Jordan, has called the Islamic State, the successor organization to Zarqawi’s group, “deviant.” The Islamic State, however, is doing an end run around Al Qaeda and other senior jihadist voices to become the dominant jihadist organization today.

For now the momentum is on the Islamic State’s side. Unlike Al Qaeda, it looks like a winner: triumphant in Iraq and Syria, taking on the Shia apostates and even the United States at a local level, and presenting a vision of Islamic governance that Al Qaeda cannot match. Yet this ascendance may be transitory. The Islamic State’s fate is tied to Iraq and Syria, and reversals on the battlefield—more likely now that the United States and its allies are more engaged—could erode its appeal. Like its predecessor organization in Iraq, the Islamic State may also find that its brutality repels more than it attracts, diminishing its luster among potential supporters and making it vulnerable when the people suddenly turn against it.

However, the Islamic State’s triumphs so far have profound implications for U.S. counterterrorism. The good news is that the Islamic State is not targeting the American homeland—at least for now. Its emphasis is on consolidating and expanding its state, and even the many foreign fighters who have flocked to its banner are being used in suicide bombings or other attacks on its immediate enemies, not on plots back in the West. The bad news is that the Islamic State is far more successful in achieving its goals than Al Qaeda has been: like it or not, the Islamic State really is a “state” in that it controls territory and governs it. Its military presence is roiling Iraq and Syria, and the threat it poses extends to Jordan, Saudi Arabia and especially Lebanon. The more than ten thousand foreign fighters under its banner are a recipe for regional instability at the very least, and U.S. officials legitimately fear they pose a counterterrorism problem for the West. Ideologically, the sectarianism it foments is worsening Shia-Sunni tension throughout the region. So the Islamic State is a much bigger threat to Middle Eastern stability than Al Qaeda ever was. In addition, young Muslims in the West find it inspiring, and those who don’t fight directly under its banners might decide to attempt attacks in the West instead in the Islamic State’s name.

The United States and its allies should try to exploit the fight between the Islamic State and Al Qaeda and, ideally, diminish them both. The infighting goes against what either organization claims to want, and it diminishes the appeal of jihad if volunteers believe they’ll be fighting the jihadist down the block rather than the Assad regime, Americans, Shia or other enemies. Efforts to stop foreign fighters should stress this infighting. The Islamic State’s social-media strategy is also a propaganda weakness: because the organization allows bottom-up efforts, it risks allowing the most foolish or horrific low-level member to define the group. Playing up its atrocities, especially against other Sunni Muslims, will steadily discredit the group.

Military efforts also matter tremendously. For Al Qaeda, the constant drone campaign has diminished its core in Pakistan and made it harder for it to exercise control over the broader movement. For the Islamic State, defeat on the ground will do more to diminish its appeal than any propaganda measure. Washington should also work with regional allies to ensure cooperation on intelligence and border security.

Some degree of continued infighting between Al Qaeda and the Islamic State is the most likely outcome. As such, the United States should prepare to confront a divided foe. The good news is that the fight within may consume most of our adversaries’ attention; the bad news is that anti-American violence or high-profile attacks in the Middle East may become more intense as each side seeks to outmatch its rival. Indeed, the January 2015 attacks in Paris may have been an attempt by AQAP, Al Qaeda’s most important affiliate, to prove the group is relevant. Yet while spikes in violence may occur, such infighting will undermine our enemies’ ability to shape regional politics, diminish both movements’ influence and discredit jihadism in general.

Daniel Byman is a professor in the Security Studies Program at Georgetown University and the research director of the Center for Middle East Policy at the Brookings Institution. Follow him on Twitter at @dbyman. Jennifer Williams is a research assistant at the Center for Middle East Policy at the Brookings Institution. Follow her on Twitter at @jenn_ruth.