Electoral College means winning most votes may not win US presidency

The United States is yet again staring down the barrel of a potential constitutional crisis as the race for the White House enters its closing stages.

With the Republican presidential hopeful Mitt Romney's post-debate momentum now bumping-up against President Barack Obama's formidable street-by-street strategies across key states, the risks of Romney winning the popular vote but not the White House were all too clear at the weekend.

Despite his lead across national polls Romney has yet to topple estimates that give Obama the edge in the so-called battleground states.

Those swing states, including Ohio, Virginia and Wisconsin, are the key to the White House, providing the path to the 270 votes needed to win the majority of the 538-vote Electoral College.

The political calculus of both campaigns is now so acutely tuned that both candidates are targeting statements not to the nation, but the interests of individual states, and specific counties with those states. Some estimates suggest that just 5 million voters in those counties could carry the election in a nation of 311 million.

In the vaunted US democracy, the race for the White House is actually an indirect election. To become president, it is not the popular vote that counts, but the Electoral College. And while whoever wins on November 6 will style themselves leader of the free world as head of its most powerful democracy, it is worth noting that the Electoral College has never been widely copied.