Or is it entirely possible for one major corporation to possess the technology, software, hardware, talent, and capital to suddenly hold the world hostage with the same quality of weapons they sell to the government ??
The answer to this question veers from the subject, but I am thinking about AI and its abilities as revealed so far and as potentially developed. So far, the AIs that we know about either would not pass or would barely pass the Turing Test. But none of them so far have reached the level that we need to consider Isaac Asimov's "Three Laws of Robotics." If one corporation develops a real, sentient AI then I think that is the answer to your question, Isaac.
Several different movie productions dealt with the (usually mistaken) idea of giving a sentient or near-sentient AI control of our nuclear arsenal or other dire weapons.
Colossus: The Forbin Project (1970, with a young Eric Braedon of soap-opera fame) dealt with a "benevolent" but unyielding AI to FORCE peace among all nations worldwide. With explosive nuclear persuasion for those who would not follow orders.
War Games (1983, Matthew Broderick and Ally Sheedy) dealt with a similar mistake. In this case, a semi-sentient nuclear control computer with an ineffective back door that allowed a young hacker to trigger the sequence that would have led to international nuclear war.
Let us not forget Arnold Schwarzenegger's epic
The Terminator (1984, also starring Linda Hamilton and Michael Beihn), with a fully sentient Skynet triggering the nuclear holocaust and with walking AI units as low-level enforcers. Then, in true Hollywood fashion, five more versions of the same... or was it six? I lost interest and lost count long ago.
And the grandaddy of many of them, though with a slightly different tone and different weaponry, was
The Day the Earth Stood Still (1961, Michael Rennie, Sam Jaffe, Patricia Neal) about interplanetary emissary Klaatu and his robot partner Gort. In the original story, Gort was the actual leader of the expedition and was an AI who would also enforce peace. (The tanks and artillery units who fired on him found out the hard way about alien disintegrator beams.) Klaatu was merely the human who could perhaps persuade people to listen to the message. In the movie, they down-played the idea that Gort was in charge.
Since I mentioned Isaac Asimov, we can't forget the movie
I, Robot (2004, Will Smith, Bridget Moynihan, James Cromwell) where the central AI that controlled ALL robots decided that the only way to protect humanity included protecting humanity from itself, thus causing a total lockdown of a non-nuclear variety. The script was an adaptation and combination of several of Asimov's short stories, some of which were cautionary tales about being careless with robotic AI, though none of the stories ever had a planet-wide robotic uprising.
To answer the question, I had to diverge off-topic. Let's stick to the thread topic and take this up elsewhere if you feel it is necessary.