Why could Sinestro master the elemental force of fear? Compared to the true horrors of the fifty two layered universes, what exactly is frightening about a pink fascist in yellow tights?
It came all at once, a horrible static burst cutting through Earth's delicate web of satellite powered communications. "People of Earth." A flicker of light and energy, as the sneering, mustached face comes into view. "This is...Sinestro, leader and founder of the Sinestro Corps. For too long, Earth has suffered under the yoke of nationalism. It is clear to me that for all of their virtues, the human race is simply incapable of governing itself in a reasonable, orderly fashion. We have come to help you. We have come because, when given the chance to help yourselves, you jockeyed for position and struggled for dominance instead of acknowledging the need to unify. We have come to save the world. The planet Earth, a source of great fear for the civilized universe, has been annexed as a protectorate of the Sinestro Corps. Do not resist, and the transition shall be accomplished with minimal strife."
In the skies, the first, best line of defense against alien invasion has failed. The Watchtower was somehow fooled into believing that the rush of negative energy was the dimensional equivalent of a sunspot. Amon Sur, Parallax, leads the space contingent of this army of psychotics, shimmering beams of the yellow spectrum of light making themselves known as the Sinestro Corps secures the fortress-space station.
"The only colony on the Earth that has declared open alliance to the Green Lantern Corps is the settlement of Coast City. Even here, Sinestro shows his limitless mercy. People of Coast City, you have one hour. Then, I shall descend upon the home of my great enemy, and I shall leave nothing standing. Leave. Quickly. The remainder of the United States of America shall be secured by Sinestro Corps agents within that hour timeframe."
Eyes glowing the harsh yellow-red of a bleeding sun, Mongol leads his war party tasked with seizing America's heartland into a sweeping formation around what is arguably the soul of the United States; Mount Rushmore. Mongol grins, envisioning his twisted visage carved over the great leaders of this rebellious nation.
"Terms of surrender for the rest of the world shall be broadcasted from the United Nations building. I do not expect the proud human race to accept their fate until they are taught how to fear. Their weaponer-guardian will be tasked with spreading the fear that must be established to bring order to this wounded, rabid world. Rejoice, earthlings. You are delivered."
Enkafos's eyes open, his three hundred and sixty fifth awakening since the end of his natural life. The mummified agent of Sinestro stands in the middle of the UN Plaza, and silently basks in the greatest city on the planet's terror, its anticipation. "Prepare." He orders his subordinates. "The throne must be ready to accept antimatter within the quarter hour."
The frightening thing about Sinestro, you see, is when this almost foolish figure talks about bringing order to the galaxy, living nightmares listen. They cheer. They unite. They work together. Sinestro can take a disorganized band of egomaniacs and psychotics and bring them together as firmly as any crack unit of soldiers. His eyes gleam with the cancerous yellow of a dieing star as he hovers over Coast City, his ring helping him keep track of the work of those that bare his name below. And Sinestro couldn't keep the smile off of his face.