Well the USA sometimes assassinates democratically elected leaders in South America, but I don't know about a war.

Well there is a theory in international relations called "Democratic Peace" which means that democracies do not tend to go to war agianst each other.

But democratic countries do go to war, just look at US

There are a few ways to look at it.

Vietnam by and large was an easily winnable war prior to the Tet Offensive. The problem was that you had the worst president in office (Johnson) micromanaging the war ala Adolf Hitler. Had Johnson let his military advisors conduct the war, it would not have dragged on for many more years, killing many additional soldiers and civilians.

As for what the OP's professor stated: He was wrong in his statement. Germany was a Democracy when it voted Hitler in. Although the elements of Democracy were hindered thanks to Hitler, it was still considered a Democracy when it started attacking everyone. And the actual argument is that liberal democracies rarely go to war with each other. Democracies still conduct war against dictatorships and others (look at Serbia, and Iraq in the 90's), but their aptitude for major continental wars is less likely.

That's rather extreme.

And I'm pretty sure China, with it's overwhelming manpower and strong military, could kick our asses as we stand now. Moreso because they simply have more people than we do. It'll be a bloody conflict that'll destroy both sides to be sure but that in itself destroys the patriotist argument that America is unstoppable in military.

War is not won by numbers(with this I mean population only), certainly not modern warfare.

That said, USA is to China what the UK is to USA.
In all seriousness though, I really do think US can still defeat China in a 1vs1 military conflict. But war seldom is 1vs1.

It depends on how you define war.

The US military could easily win the battle against the Chinese military if they went toe to toe, even with allies the USA would probably win.

That doesn't mean the US could hold the chinese mainland for very long. Over a billion people would simply be nearly impossible to manage. Especially if they were hostile to you. If the USA and allies were in an iraq like situation in the Chinese mainland it would be bloody expensive. Of course war isn't always about occupation either.

How would USA go to war? Hey China can you borrow us more money so we can pay our solders to fight yours;..

Anyway the only war USA should have now is the war against the high unemployed rate.

Meh, it was just a hypothetical "what if" question. Not something that's likely going to happen.

It would be funny to set all the different ethnic groups in China against each other though. Divide and massacre.

Yeah your Belgians are used to it ^_^'

And I find it really disgusting that you would consider something like that funny.

Well, I find it disgusting that a lot of Chinese people still admire Mao Zedong to this day. He killed(indirectly) what? 100million Chinese?

I just want all the different ethnic groups to be freed from the Chinese government. They have to right to be free, but that will only happen through violence and turmoil in a regime like the "People's Republic of China". All I can do is sit back and watch. Well, I could do something to help, but consider me a coward.. xD

It's hard to explain, but I've always been fascinated by wars.