If the US suddenly went to a Parliamentary system [with no other changes made except ditching the P/VP and moving the rest of the executive branch under the control of the PM], Harry Reid or Nancy Pelosi would become Prime Minister. Not sure if the PM comes from the upper or lower house or if it varies by country.
Not a completely valid comparison, but...
Carol [who teaches US Govt but only skimmed the Electoral College but set aside all of Election Day to discuss it in more detail...]
