מלכים א, פרק ט״ו, פסוק כ״ז

A military campaign on the western border sets the stage for a dramatic political assassination within the leadership of Israel. As the Philistines threatened the region, King Nadab set out to secure the area, ultimately laying siege to the Philistine city of Gibbethon [ביאור שטיינזלץ]. The timing and location of this military operation provided the perfect opportunity for a rebellion. The uprising unfolded exactly while the king and his army were encamped outside the city walls, actively engaged in the siege [מצודת דוד, מצודת ציון].

The conspiracy was not the work of a single individual; rather, it involved an organized group secretly banding together with the specific goal of overthrowing the monarch [מצודת ציון, ביאור שטיינזלץ]. The environment of the active siege proved critical to the success of the assassination. Because the camp was populated entirely by soldiers, Baasha was able to take full advantage of the isolated military setting. He successfully persuaded members of the army to join his cause and cooperate with his plan. With their backing, he was able to execute his plot and strike down King Nadab [ביאור שטיינזלץ].