I will place a secret subliminal message in my dA avatar picture that will brainwash people to want to do my bidding and they will not be happy unless they can get others to look at it too so it will go viral and will spread around the world and within 24 hours the world will be mine. Look at my avatar. You are getting sleepy, you are getting very sleepy. At the count of three you will awaken and will desire to do nothing but please ~ARTificialphanTOM. You will not be happy unless I am happy. One, Two, Three.
I would buy America with my semi-legally earned funds, and use the multiple weapons & military at my disposal to invade & take over all the other countries. Russia & China will be difficult, but I can easily bribe them with booze and chocolate
I'll become a preacher for lost souls (People who have nothing left/ People who have lost their way), I will tell them of the great purge and of its arrival bathed in blood and sheltered by fire. Then, once a reasonable amount of people are enlisted into my church, I will choose a select few to become my elite soldiers. I will name them the "Pacifiers". Not too long after I have established by elites, I will force the remaining church followers to train in military combat or else they will watch their families die. After my army is complete, and hidden within my church's catacombs, I will assign each one to attack major areas of the US to get the Federal Gov's attention. My soldiers WILL die, but not for nothing. Because with so many distractions, it will be easier for my elites to attack the White House. I chose my elites from powerful politicians and corruptible soldiers, allowing for access to military weaponry. So naturally, I came prepared for my White House assault. Holding the President hostage, I demand for the US soldiers to cease fire or else the President dies; Though of course there are racist soldiers who would enjoy seeing Obama die so once my threat goes unheard..I detonate bombs inside congress, the Abraham memorial, and shoot Obama in the head. With the nation in shock I seize the reins of the US government and inspire my newly appointed army to attack China. Our superiority and surprise attacks succeed and slowly..country by country...We dominate their governments as I inspire the poor despots of these conquered lands to join up with my noble cause to purge the world of darkness. But I know there are power seekers who would wish to take my throne (and judging by how the process of world domination could take several years, I am mostly likely near 60 years old) ; So I send out nukes to decimate all of Europe, China, And Russia. I set all nukes to hit every spot in the world, ready to press the button once someone rebels. And of course, a small band of rebels comes up and I destroy the world. Sending it into a nuclear holocaust. I get into my climate stability suit and head into the bunker, near Earth's core. Once there, I activate the drills with nukes prepped to destroy Earth's core. The last thing any survivor witnesses is oblivion.
After you overtake the U.S., wouldn't it bring attention to worldwide countries, especially America's allies? Some of those countries may even try to take you down, and most will strengthen their military to defend themselves.