Why are most country government buildings Roman Imperium like?

The Romans copied the Greeks; their buildings were well-proportioned and exuded nobility and something close to perfection. They took into account perspective, angles of viewing, materials, function and the arts.

Hitler and his architect, Speer, reignited a fad for overwhelming civic buildings. Thank heavens it seems to have passed.

Many Western countries draw their governmental systems from the ideas first conceived by the Greeks and Romans. Democracy, equal representation, etc. all were first born in those societies. Thus, governmental architecture is often a tip-of-the-hat to those societies.
Also, the Greek style of architecture (and the Roman style that was, perhaps, one of the first instances of plagiarism) relied on perfection. This is just one example of the society’s fascination with perfection. Angles, perspective, etc. were all designed to be perfect in the eyes of the beholder. Governments often strive for this same perfection.

Not much of that in my country. We have very mixed styles of architecture of our government buildings. But sure, there are some renaissance facades.

The basics of democracy and classic republicanism have their roots in the classical eras of Greece and Rome, Second week lesson in HS American Democracy. BTW Hitler and Speer were bungling poseurs, losing the message in massive copies.

ouch

Because USA Fancies itself as a Romanesque imperial power, emulating the Senate for example with similarly crude instincts for domination and control, and similar lack of cultural values or respect for foreign autonomy.

Cause the Romans are bad ass.