Those that do not learn from history are bound to repeat it

One only has to read history on the fall of the Roman Empire to see that the United States is on the exact same track.
A few leading reasons that contributed to the fall of Rome:
1. The Romans became fat, greedy, and corrupt. Senators were being bribed constantly.
2. The Empire became too big. So big that it could no longer be governed.
3. The Romans allowed foreign tribes and millions of people to invade it's northern borders.
4. The Romans had a growing trade deficit.
5. Massive division. It became so bad that the empire was forced to split into two.

Now why is America similar?
1. Americans are fat and greedy. And we are becoming increasingly corrupt.
2. America has stretched the military and economy too thin. We are fighting too many wars in too many places.
3. Illegal immigration is out of control. We are being INVADED by millions and millions of people who we can't afford to take care of.
4. Our trade deficit is astronomical.
5. We have division all over this country. After the last election, everyone was talking about wanting civil war between red and blue states.

I don't see America surviving to 2050. Maybe we need to consider what we are going to do when America falls. Because whatever replaces it won't be a free and democratic country.

The only thing I disagree with is your conclusion. "..it won't be a free and democratic country."

We passed that milestone when we decided to become an empire. About 100 years ago. We've been an oligarchy ever since.

that wasn't the problem, slaves were doing the labour. The fights at the northern border were due first to Roman expansion, not the contrary.

The split came late in the story of the Empire and is not comparable with the "split" in today's US.

In essence, the "fall" of the Roman Empire to a contemporary depended a great deal on where they were and their status in the world. On the great villas of the Italian Campagna, the seasons rolled on without a hitch. The local overseer may have been representing an Ostrogoth, then a Lombard duke, then a Christian bishop, but the rhythm of life and the horizons of the imagined world remained the same. Even in the decayed cities of Italy consuls were still elected. In Auvergne, at Clermont, the Gallo-Roman poet and diplomat Sidonius Apollinaris, bishop of Clermont, realized that the local "fall of Rome" came in 475, with the fall of the city to the Visigoth Euric. In the north of Gaul, a Roman kingdom existed for some years and the Franks had their links to the Roman administration and military as well. In Hispania the last Arian Visigothic king Liuvigild considered himself the heir of Rome. Hispania Baetica was still essentially Roman when the Moors came in 711, but in the northwest, the invasion of the Suevi broke the last frail links with Roman culture in 409. In Aquitania and Provence, cities like Arles were not abandoned, but Roman culture in Britain collapsed in waves of violence after the last legions evacuated: the final legionary probably left Britain in 409. The last western emperor, Romulus Augustus, was deposed in 476 by the Germanic chieftain Odoacer.

http://en.wikipedia.org/wiki/Roman_Empire

the Western part fell first. But it was due to massive invasions due probably to climatic/environmental changes in the north. To achieve the same effect in the US it would mean that all the Western US part would fall to a massive Chinese invasion. We are not there... yet ?

Senators were bribed much more during the rise to Empire in the latter days of the Republic, very early in the expansion, than during the decline. They ahd real power in the early period, and were worth bribing. By the settled decline of the Empire, a Senator had scant power, and was not worth much on the open market.

It is true that the Empire did expand beyond the capacity of available means to control it. The most important lack was not modern communications, for imperiums much larger were held together with similar physical technologies. The real lack was of an effective and well organized civil service bureaucracy, such as China pioneered. The Roman "civil service" was always a patchwork of Imperial household slaves.

The Romans hardly allowed anyone to invade their borders. Their border garrisons were overwhelmed by desperate fighting men, themselves refugees from the depredations of even more hardy fighting tribes stirring in the Eurasian steppe.The Romans used, and skillfully, every element of arms, diplomacy, and bribes available to secure the situatuion, but it was beyond successful coping, and largely for external reasons.

Rome did have a serious trade deficiet, and this was wholly self imposed. Rome exported great quantities of specie for luxuries, many of them ephemeral items to be destroyed in the Games. Continuing to act so after the Empire had ceased to be an expanding enterprise did great damage, but while it was expanding, did little harm.

The splitting of the Empire into two was not a result of divisions of any political sort. It was an arrangement of districts set up in accommodation of the second factor mentioned, its great size. The divison, into either four or two parts, depending on the period, meant someone with executive authority was near enough at hand to deal with any crisis. It also provided a species of on the job training, as the custom was to appoint a designated imperial heir, often a man adopted as an adult into the Emperor's family after a successful career at arms, princips over one of the districts, so that he would have some experience at ruling when he succeeded to the throne itself.