This is an interesting debate. On one hand you have a movie about an invasion of the United States by a coalition of forces backed by the old Soviet Union. On the other hand you have a television series about a terrorist attack that destroys a number of cities in the United States by the use of nuclear weapons. At the time of release for both films, both seemed plausible, but were either productions realistic, and if so, which was more realistic?
Red Dawn
In Red Dawn, the domino effect took place in Europe and South America; however, this time it fell in reverse. The Soviets were able to seize all of Eastern Europe, and many parts of Western Europe. Meanwhile, Communist-backed guerillas were able to seize many South and Central American nations. The constant threat eventually led to the collapse of NATO leaving the US to fend for itself.
Early one morning, the Soviets launched a massive attack on Middle America seizing a large chunk of the nation while disabling our nuclear capabilities. During the seizure of one small town a group of teenagers escaped into the wilderness to form their own guerilla group to strike back at the Soviet forces. Over the course of nine months they dealt repeated hits on units that thought they were safe in occupied territory. Eventually, the Soviets were able to lay traps for the teen-aged insurgents which led to a major battle led by only two of their members who would eventually give their lives so that their last remaining members could escape to safety.
Was this movie realistic? Heavens no. The political climate of the 1980s would never have allowed the Soviets to seize that much control and the USSR's financial resources were so strained that such an attack would have been financial infeasible. To add to the silliness, the Soviet soldiers were represented as they often were in movies of that time: overconfident, abusive, and incompetent. This made them easy pickings for the heroes of the movie to kill by the hundreds while taking minimal casualties themselves.
Jericho
Jericho was shown on television during the heart of the Global War on Terror. A small town in Kansas one day finds that a large number of major cities in the US have been destroyed by nuclear attack from sources unknown. Over the course of their first year, they have to cope with dwindling resources, marauding paramilitary forces, potential attacks by neighboring towns, and the usual personal problems of living in a small town.
In the show's second season it is revealed that a corporation hoping to seize control over the US, by removing key locations where the government would fall back on, initiated the attacks. This leads to a fracturing of the United States, with the loyalists of the nation forming east of the Mississippi, and those loyal to the corporation to the west (with Texas claiming independence and neutrality). In the show's finale, the company is exposed to Texas and thus starts the Second Civil War. Unfortunately, the show would not be picked up for a third season, so no one knows how it might have ended.
Was this show realistic? Unfortunately, yes. The human spirit of survival was shown in the citizens and leaders of Jericho as they banded together against terrible odds ranging from starvation, to bitter cold, all the way to simple internal politics. The marauding paramilitary group held a remarkable similarity to groups like Blackwater that have come under fire for working outside of the standard military rules of engagement. The company Jennings and Rall bears a great deal of similarity to companies like Haliburton or Kellog, Brown, and Root that have received numerous contracts in countries where the Global War on Terror are being fought. Some times the realism of the show was almost frightening.
So, the obvious winner is Jericho in the realism category. Fortunately, both programs are nothing more than works of fiction and hopefully act as a warning to what might happen. If not, they're both pretty darned entertaining.