In The Sum of All Fears movie, the bad guys are Neo-Nazis.
In The Sum of All Fears book, the bad guys are Palestine terrorist.
>Meanwhile, a small group of PFLP terrorists, enraged at the looming failure of their crusade against Israel, come across the lost Israeli bomb and use it to construct their own weapon, using the bomb's plutonium as fissile material. The terrorists enlist the help of disaffected East German physicist Manfred Fromm, who agrees to the plot to exact revenge for his former communist country's reunification as a capitalist democratic state.
>The terrorists agree to detonate the weapon during the Super Bowl in Denver, planned to coincide with a false flag attack on U.S. forces in Berlin by East Germans disguised as Soviet soldiers, aiming to begin a nuclear war between the U.S. and the Soviet Union. The East Germans hope that the war will eliminate both superpowers and punish the Soviets for betraying World Socialism, while the Palestinians hope the attack will destroy the Israeli-Palestinian peace agreement and end U.S. aid to Israel.
>When the terrorists are captured and interrogated by Clark in Mexico City, they implicate the Iranian ayatollah in the attack. Ryan lies and claims that Qom was destroyed. The terrorists then reveal that Iran was not involved, and that their deceit was meant to discredit the United States and destroy the peace process, allowing the campaign against Israel to continue.
>The terrorists are executed by beheading in Riyadh by the commander of the Saudi Arabian special forces using an ancient sword owned by the royal family of Saudi Arabia. Later, the sword is presented to Ryan as a gift. In the sequels, the gift (combined with his origins as a Marine) inspires Ryan's Secret Service codename of "Swordsman".