They will use one of several (interesting) points, one of which is how each swing state voted.
|State||Obama||Romney||Difference||Percentage of Winning Candidate|
At this time, Florida is also trending towards Obama (they have not yet finalized their count), although it appears that every county in Florida has finalized their votes. Florida is included in the following numbers.
President Obama got 50% of the votes (59,721,271) to Romney's 48% (57,095,396). The difference was 2% or 2,625,875 votes. That means that 20.75% of the difference between Romney's and President Obama's votes was in the swing states.
All of them went to Obama, most of which with a relatively large relative difference. Now, if you had asked (most) people before the elections, most would have predicted that at least one swing state would give its electoral votes to Romney.
Also, why was 20.75% of the difference between Romney and Obama in those states? I would have expected them to be at most 5% of the nation wide difference. Those were, after all, "swing" states. States that were supposedly really close.
20.75% of 2% (or .415%) of the nation were what mattered in this election.
Mark my words, there will be calls of election shenanigans before the end of the week. In fact, they may have already started.