According to the national polls, the election is a dead heat, but this is not a national election. It is a nation-wide election, in which the fifty states and the District of Columbia each go to the poll and vote their choice. Whoever wins in each state wins that states Electoral College votes. It is not the candidate with the most votes nationally that wins but the one that wins at least 270 electoral college vote. For example, if Obama wins California, he gets the 55 votes of California and if Romney wins Texas, he gets the 38 Texas electoral college votes.
Each state's electoral votes is equivalent to the number of senators (2), plus the number of members of the House of Representatives (53 in the case of California = 55 votes). So after the election in each state,, the vote is tallied up and the winner gets that states electoral votes eg. New York, 29 , 2 +27. You then add it all up and the candidate who gets 270 wins the presidency.
There are 538 electoral college votes, made up of 100 from the Senate (each state has two senators, California as well as Maine. Size does not matter,.Each is equal here). There are 435 from the House of Re[preentatives, here it is Representation by population. The larger states eg. Texas (2+36) gets more than Rhode Island (2+1=3). The District of Columbia has 3 votes (no senators, because it is not a state, but gets 3 Reps.). So that makes it 538 and 270 is the acceptable majority.
Strategies are worked out to get that 270. Polls are regularly taken by political parties campaigns and decisions are made to target or not to target certain states with money, ads and actual campaigning. As the campaign goes on, this becomes more critical. Resources must be judiciously spent, so some states will be dropped as not winnable and others are heavily targeted and in some cases, those states where you are comfortably ahead sees less and less resources, so that they can be shifted to closely contested states, especially the "swing" states of Ohio, Michigan Florida, Colorado etc. In this respect campaigns are very fluid and decisions are made week by week , day by day. It requires thousands of foot-soldires, staffers, lawyers and managers with tens of millions of dollars. The spending in this election is already over $1 billion and we have two weeks to go, when the heaviest spending is required to blanket states with television/radio ads., social media, placards, leaflets and door -to door visits, with leaders/ candidates flying in and out.
The intensity is incredible and the attacks become more and more vociferous and vitriolic. Pummelled and badgered the two candidates, straggle home, drained but hopeful