> The allocation of seats to each member state is based on the principle of degressive proportionality, so that, while the size of the population of each country is taken into account, smaller states elect more MEPs than is proportional to their populations.

Anyway, it's not a direct comparison; MEP elections correspond to the House of Representatives, and there's no figure with the same centrality as the US President.

Most importantly, parties in the EU are primarily local and campaign on a local basis. There are trans-party coalitions like the EPP, but identification with them is weak. Whereas you can sample random Americans from across the country and find they identify as (and even are publicly registered as??) Democrat and Republican, and with a strong consistency across the country as to what those stand for.