In February 1968, the North Vietnamese Army and the Viet Cong launched a general offensive in Vietnam during Tet, the Vietnamese New Year. From mid-1966 onward, the North Vietnamese had found themselves under increasing pressure from American and South Vietnamese forces. They were far from defeated, but they were weakening and the likelihood of their military victory was receding. The North Vietnamese decided to reverse the course of the war militarily and politically by marshaling available forces, retaining only limited reserves and going on the offensive throughout South Vietnam.
The attack had three strategic purposes. First, the North Vietnamese wanted to trigger a general uprising against the Americans and the South Vietnamese government. Second, they wanted to move the insurgency to the next stage by seizing and holding significant territory and resisting counterattack. And third, they wanted to destabilize their enemy psychologically by demonstrating that intelligence reports indicating their increasing weakness were wrong. They also wanted to impose casualties on the Americans at an unprecedented rate. The American metric in the war was the body count; increasing the body count dramatically would therefore create a crisis of confidence in the U.S. public and within the military and intelligence community.
General Offensives and Crises of Confidence
From a military standpoint, the offensive was a failure. The North Vietnamese military was crippled by its losses. While seizing Hue and other locations, the North Vietnamese were unable to hold them. But they succeeded psychologically and politically by raising doubts about U.S. intelligence and by creating a political crisis in the United States. In war, perception of the enemy's strength and will, and confidence in your own evaluation of those things, shifts the manner in which one fights. The U.S. intelligence estimate before Tet was more right than wrong, but by marshaling all forces for a general offensive, the North caused U.S. trust in that evaluation to collapse. Even though the North Vietnamese were militarily far weaker after the offensive, the military failure proved less relevant than this creation of a crisis of confidence.
The use of a general offensive to reverse military decline is not unique to Tet. The Germans did the same in their offensive in 1944 at the Battle of the Bulge. While the Germans also had a military intent, their psychological intent was as important. Before the battle, the Allies thought the Germans were finished. They were, and so the Germans had to show they still had power. They accordingly threw their reserves into a battle to break the Allies' nerve.
When launched at a time when it is assumed it could not be launched, the general offensive is a powerful weapon. Such an offensive is now underway in Iraq. When we step back, we see a broad offensive by Sunni jihadists underway in a range of countries. In Afghanistan, a massive summer offensive is underway in parts of the country once regarded as secure. To the south, the Pakistani Taliban launched a major offensive a few weeks ago that sparked a Pakistani counteroffensive, putting the Pakistani Taliban on the defensive. In Syria, while the Islamic State (formerly known as the Islamic State in Iraq and the Levant) has not surged, it also has not declined. Southern Jordan has meanwhile seen clashes between jihadists and government forces. In the Palestinian territories, Hamas has announced, though not launched, a third intifada. To the west, Egypt is experiencing terrorism, while in Libya jihadists have asserted themselves in various ways.
The Question of Coordination
Like the Vietnamese and Germans, the jihadists have, broadly speaking, been on the defensive in recent years, and in many cases they had been dismissed as broken. They differ from the Vietnamese and Germans in the sense that they do not constitute a single force. The question remains, however, whether there has been coordination between these offensives. Clearly, the Jordanian, Syrian and Iraqi offensives are linked. Not so clear is whether they are operationally linked to events in Afghanistan and Pakistan or North Africa. To the extent there was coordination, it would have come from Saudi Arabia. As one might imagine, Saudi actions are deliberately murky, so it is difficult to establish anything definitive here. But the Saudis are most threatened by the prospect of a U.S.-Iranian entente. The Saudis also find the jihadists useful for domestic political purposes and as a lever to maximize regional Saudi influence.
There are small hints here and there of coordination, such as this video. But mysteries always have small hints that one can pretend combine to prove something. So far, we see nothing definitive indicating overall coordination. But in a certain sense, it doesn't matter. These uprisings have occurred close enough to each other that they have had the same effect regardless of whether they were coordinated -- giving rise to a sense that the situation in the region is destabilizing dramatically and that jihadist strength has been underestimated.