This is a broad question. And it needs to be noted that ancient Rome can be said to have three different governments over a time span from appoximately 700 BC BCE to 453 AD CE. The United States has a relatively young existence compared to that of ancient Rome's. The government of the United States at one time had two major things in common with all three ancient Roman governments. Each had the major flaw of denying the vote to women and each had the institution of slavery as being legal. The flaws mentioned do not now exist in the USA. In ancient Rome the flaws remained intact until the end of what is called the Western Roman Empire.
Major differences:
Anyone born in the United States is automatically a citizen.
In ancient Rome, persons born in Rome and in specific places in the kingdom, republic and imperial Rome were automatic citizens. Thus we see that citizenship is universal in the USA, but has specifications in all the "Rome's".
The early government of Rome was a monarchy. The USA was always a republic.
The "republic" of Rome had a government which followed written laws and there was a balance of power within the government. The balances of power, on paper and in some practices qualified to be called a "republic". The USA also is a republic.
The ancient Roman "republic" can be called as such because in one form or another, there were elections, there were separate bodies of law and executive action was at times separate from legislative. Rome also had a judicial system. Technically speaking for the era in which it existed, the Roman Republic was a step forward in the development of the history of governments.
In contrast to the Roman republic, the United States has a "textbook" republic. It has free elections, and separate bodies of legislation, executive processes to carry out the will of the legislative branch and a judicial system designed to ensure the laws all meet the requirements of its wriiten laws found in the US Constitution. Please understand that the details of each of the republics called to question here are written in a broad manner. To do it otherwise would require many pages of text.
After the demise of the ancient Roman republic, it was replaced in fact by what can be called a "constitutional monarchy" with a vital notation.
The notation is that the constitutional part was created by the monarch (emperor).
Dinosaur King - 2007 Ancient Roman Holiday was released on: USA: 10 October 2009
USA
Our government is much like the Roman's republic
Probably because it was possible for everybody to vote. The USA's government was based off of the Roman republic.
The most outstanding contribution of ancient Rome was the development of the their government into a republic. The ancient Roman republic was not perfect, however, the republic's structure of having a "balance of powers" in a manner of speaking, led to the USA's government of having powers shared by three different branches of government. The framers of the US Constitution created a republic where powers are balanced between the legislature, the Federal Court system and the executive branch. However, this balance between branches of government does not resemble at all the branches of the government of the Roman Republic, which were totally different. The concept of balance of powers comes from Polybius, the ancient Greeks scholar, and the work of Montesquieu, the famous the 18th century French philosopher, rather than Roman political thought. The US branches are more akin to that of the British government of the time of the drafting of the US constitution (except for the monarch) which was the model used by Montesquieu. Although several ancient civilisations developed written laws before the Romans, some of the key principles of Roman civil law have provided part of the foundation of the law of many modern countries. These were: citizenship status and citizenship rights, equality under the law, the right to have a proper trial and to defend oneself, the right to appeal, that the burden of proof rests on the accuser and not on the accused, that it is the exact form of actions and not intentions or words which is punishable, that a law deemed unreasonable or unfair can be repealed, and that no Roman citizen should be tortured.
The European Union does not have a government. It is an organisation of 27 different independent countries, each of which has its own government. The USA is one country with one government.
The USA is much larger. The USA is wealthier. They have different cultures. They have different types of government.
Among many things some of the more important concepts borrowed by the USA from ancient Greece and ancient Rome were the rights of citizens to vote; to have people accused of a crime be entitled to a jury trial. In ancient Athens for a good period of time, there existed a "democracy" From Rome, the idea of written laws. In addition Rome also had a system for citizens to vote. These essentials for a representative government were lost for ages. The USA placed these basics in US laws. In the era that the USA was formed, few nations had these basic rights in law.
Both Rome and Egypt improved modern day USA - especially the capitol - things such as the obelisk in the capitol, and much of the architecture is Greco-Roman. Both were mainly monotheistic, and both have different civilizations using forms of their old languages today.
Democracy. Democracy was a Greek concept. Rome did not have a democracy. The ideas borrowed from Rome were the concept of checks and balances of powers and the veto
The government of NZ is part of a monarchy and a constitutional democracy The government of Australia part of a monarchy a constitutional democracy and a federation of states. The Government of the USA is a constitutional democracy, A republic, and a federation of states.
Victoria Roman was born in Miami, in Florida, USA.