Why the difference in mpg between US and EU cars for basically the same thing? So basically we are getting screwed.

Some examples (I'm sure there are more) ... I tried to pick out similar vehicles:

Edge US - 24 mpg hwy
Kuga UK - diesel - 44 mpg (combined)

Focus US - 35 mpg Hwy
Focus UK - 42.8 mpg Combined
Focus UK - Diesel 65.6 mpg

Aveo UK - 51.4 mpg combined
Aveo US - 34mpg hwy

Evil oil companies in kahoots with the auto makers...

Because gas prices this high are a relatively new problem for us. Europe has had them for years, thus causing the change in what consumers wanted in a vehicle. We are slowly starting towards that now. Look at how the automakers are tooling down truck manufacturing.

But why should the American people pay for basically the same car and get less mpg? We could be getting 10-20 mpg higher. We should have been getting those cars here all along.

The primary reason is the amount of crap the EPA has made the car manufacturers put into the cars in order to clean the air...
Catalytic converters and other emission equipment has driven the miles per gallon into the toilet
None of the European cars mentioned can be sold in the US because they don't pass the EPA requirements... and some states are even harder than the EPA requirements...

Right on the money! They call them 'grey vehicles' and to have them pass the USA standards it costs a fortune in add-ons in Elizabeth, NJ..I used to work alot with overseas people being transferred here and some of them would bring their vehicles only to discover they had a $5k bill to 'fix' their car to the USA EPA regs. Needless to say, we would 'highly discourage' them from trying to do this..

I noticed that diesel cars get better gas mileage. I wonder why that is? Then again, I don't know anything about cars so if you start talking about pistons and converters and such and such I'll be lost.

The Euro models generally have smaller engine options vs. US models. V6s are probably unheard of as an option on smaller cars over there. I checked the links to your listed cars. The Euro Focus had a 1.4L engine standard, the US a 2L as the standard. So why don't they offer the small engines here? My guess because Americans wouldn't like putting around in a tiny 4 cylinder.

The Brits, where your comparisons mostly came from, also figure MPG a little different than us. 1 U.S. mpg equals 1.2 mpg in Britain due to them using Imperial gallons. I don't feel like crunching the numbers, but that should bring the UK vs US model MPG comparisons a little closer.

Crap, I was hoping for some kind of conspiracy.

Diesel fuel has more energy available per gallon.

Sman-
You mean they drive lawn mower engines??

Pretty much, yeah. That's what I was getting at in my first response. Europeans have been paying through the wazoo for longer than we have, so the market demanded more economical vehicle solutions. Like lawn mower engines.

Someone made a good point, European cars determine MPG a little differently than our cars. As said, the catalytic converters and other emission equipment has to answer to more regulation in the USA, affecting mileage. Guess it is a trade off, folks have to decide or revisit priorities. Now that gas is so high our reality is shifting.