The Invaders: alien beings from a dying planet. Their destination: the Earth. Their purpose: to make it "their" world. David Vincent has seen them. For him, it began one lost night on a lonely country road; looking for a shortcut that he never found. It began with a closed deserted diner and a man too long without sleep to continue his journey. It began with the landing of a craft from another galaxy. Now, David Vincent knows that the Invaders are here; that they have taken human form. Somehow, he must convince a disbelieving world that the nightmare has already begun.And with that prologue that opened every episode we have the plot of the 1967 television series starring Roy Thinnes as architect turned crusader David Vincent. If you're of the generation where alien invasion series involve glacial plots about Earth people who aren't particularly interested in the invasion and pass the time flirting or bickering and aliens who can't be much bothered with getting on with the invasion when there's so much flirting and bickering to do, then The Invaders is a bit of a surprise. These Invaders actually do some invading. They breed killer insects, throw hurricanes at Washington DC, smuggle in poison gas, infiltrate governments, and sabotage moonshots. This keeps Mr Vincent very busy as he hops around the country foiling the Invaders' plans.
In a way, the format is an interesting twist on the chase story. The Invaders are hunting Vincent, so he has to keep constantly on the run, but Vincent is also hunting the Invaders, so they must remain eternally on guard against the resourceful Earthman who strives to expose them to the world. It's also interesting because, unlike most adventure stories, neither side in the battle has an easy time of it. Vincent is a man alone. No one believes his wild stories and he has a public reputation as a crackpot. Worse, he can't produce any evidence of the invasion because the Invaders are very good at covering their tracks to the point of rigging their bodies to self-destruct if they die. However, though it's never explicitly stated, the Invaders are limited as well. There are only so many of them and the task of waging a war over interstellar distances from a dying planet is a tremendous bottleneck that forces them to use Earth manufacturing and technology to supplement their own. Secrecy is so vital to them that it's clear that their plans would fail utterly if the government believed Vincent's warnings. It also helps dramatically because the need for a low-profile invasion means that special effects are few, but when they are used, they're spectacular. Not a small feat for 1967.
It's a beautiful setup, but this is still 1960's television, so the writing is deliberately formulaic. A strange event occurs, Vincent goes to investigate, no one believes him, the Invaders cleverly cover their tracks and try to kill/brainwash/hypnotise/bribe/threaten/frame/blackmail Vincent without success, bystanders drawn into the conflict face death or their inner demons, etc. However, though our hero prevails, his victories are often small ones against the greater threat. This has the hazard of being repetitive, but one of the selling points of the series is the feeling of paranoia that drips from the stories. Is the policeman merely a sceptic or one of them? What about that sweet little old lady? Who can be trusted? Can anyone?
It's ironic that creator Larry Cohen managed to shoot himself squarely in his political foot with The Invaders. Taking his inspiration from the Hollywood blacklisting of Communists in the 1950s, Cohen wanted to make "a mockery" of fears of infiltration by using aliens instead of Communists as a threat. An interesting point, but he never seemed to notice that the mockery angle doesn't quite work because the whole point of the premise is that the Invaders are real. But a series about a paranoid crackpot who is just a paranoid crackpot has limited mileage, so contradictions be damned.