Prepare the ground over a period of approx. 2 - 12 years for an invasion in a miserable eastern country that sits on mythical treasures. Any massive catastrophe that occurs back home during that period can be attributed to that country's evilness. Over expensive DC private dinners, the catastrophe is considered a godsend.
A few weeks before the invasion, visit some zombi organisations, whose members are at best near-starved, ridiculous creatures that have long ago lost all self-respect and credibility. You try, not too hard necessarily, to get their approval for the imminent slaughter.
The disapproval you get you smirk at because you know it will be short-lived (see below). You get some approval though, which pleasantly surprises you. This will make for a good laugh back home.
Invade. Use clever, intelligent and genial bombs that can spot any civilian wherever they may be hiding and begin the slaughter. As there have to be casualties on both sides, so that you can call that thing a 'war', hit your trusted poodles a few times (you still call them 'allies' after some remote, tear-jerking, tradition), to make sure some bodies are returned home wrapped in formerly glorious flags. This also makes for a very good laugh back home.
Engage in land warfare so that you lose some pawns on your side (never exceed the top two figures). Just enough to keep the flame burning for your home viewers. Allow a tear to trickle down your cheek.
Stop the official count of the civilian casualties when they reach the low 4 figures, as this might trigger some discontent among your (non)voters. There is always the danger that carefully preserved dormant brains might be sparked off into remembering why they crossed the ocean in the first place.
If you suspect that some foreign correspondents are going to report casualty numbers different to yours when you storm the city and bomb all possible places that may contain human life, shoot them. Leave standing those who speak incomprehensible languages understood by so few that you couldn't care less.
Make sure the whole escapade lasts between 3-4 weeks. That's the concentration span regarding serious events back home. Now that all foreign journalists and reporters are dead or sent home, welcome to your own private playground. Your embedded hi-fi speakers are in raptures as to the glory of the accomplishment. The markets recover (you have, in the meantime, recovered yourself all the costs of the mission by simple speculation - you are, after all, the only holder of inside information).
At this point, CNN begins an intensive enema course that lasts between few days to few weeks showing over and over again the same footage of the 300-500 civilians that enthusiastically welcomed you as a liberator, while the same faces are being spotted looting all they can lay their miserable hands on. Sometimes CNN gets muddled up and shows earlier footage too. CNN's viewers are momentarily confused but they immediately revert to their normal state of encephalic vacuum.
You call for a democratically elected government for that country that consists of your retired army officers, who eagerly applied the job. You choose them carefully to fit the bill. These highly paid jobs, with all sorts of benefits, are very popular. There is a lot of disgruntled barking amongst your poodle pack 'cause they are left out. They are easily appeased with your visit to Ireland. (Everybody holds their breath in case you say 'South' instead of 'Northern')
The starved hyenas that refused to help you in your mission (see 2 and 3 above), misleading their own people under banners of superiority, humanitarianism, maturity and sensitivity, are now following you closely to grab any morsel you can spare. Back home you are in stitches over the pitiful sight and I really cannot blame you.
While your administrators are ironing out the last details, you are already planning the next campaign. You sigh, as the next ones may not be such rich pickings. How often, after all, one can get hold of one tenth of the planet's oil reserves in 20 days. But, hey, it doesn't matter. The recipe works and it is good.
You can be more than sure that within the next two years that it will take you to prepare for your next campaign, a horrific massacre will take place back home with hundreds to thousands of casualties, something that will give you all the moral standing and justification you need. And if not you, your successor. Unfortunately, the recipe is not as refined yet as to ensure re-(non)election.
Last but not least. Bring back few horribly mutilated, barely alive, little war orphans wrapped in your flag and provide them with your infamous social security. Nobody then will know that you did it.
PS You might want to consider changing the flag from 'stars & stripes' to stars only, as there will not be much room left for stripes soon.