By STEVEN R. HURST
WASHINGTON (AP) - The outcome of the hard-fought but still deadlocked presidential race between President Barack Obama and Republican challenger Mitt Romney will be decided Nov. 6 by a small percentage of voters in just nine states. That's because presidents are elected not by popular vote, but by the Electoral College.
The system was born from an 18th century political compromise. States are allocated a fixed number of electoral votes based on population. In almost all cases, whoever wins a state wins all of its electoral votes. And the candidate who captures a majority of the 538 electors becomes president.
Most states are reliably Democratic or Republican, but neither Obama nor Romney has a lock on enough states to win a majority of electors. That means the real battle is for the nine "swing states" _ those where the outcome is uncertain. Whoever can carry enough of those states to bring his overall electoral vote total to at least 270 will win.
Nationwide polls, which show the race a virtual tie, do not necessarily predict the outcome. A candidate can win the most votes nationally and still lose by failing to accumulate a majority of electors. What's important is what happens in the swing states. And, for the moment, Obama appears to have an edge.
The Electoral College:
Each state is granted one presidential elector for every member of Congress: one for each member of the House of Representatives, where seats are allocated according to population, and two more because each state has two senators. That guarantees that each state will have at least three electoral votes. The District of Columbia gets three electors even though it doesn't have full congressional representation.
In most states, the popular vote winner captures all of that state's electors. The only exceptions are Nebraska and Maine, which award electors proportionally.
The system was written into the U.S. Constitution to overcome concerns by small states that they would be left voiceless among their larger-population brethren. The solution was a middle ground between those who wanted the president to be chosen by Congress and others who pushed for a nationwide popular vote.
In what is largely a formality long after the winner has been determined, each state's electors will meet on Dec. 17 in their home states and cast their votes for president and vice president. Congress will meet on Jan. 6 to conduct an official tally.
The Electoral College system can produce two anomalies. As happened to then- Vice President Al Gore, who lost to George W. Bush in 2000, a candidate can win the most popular votes but lose the presidency. Or candidates can be tied for electoral votes, 269 each, which throws the tie-breaking decision into the House of Representatives. The choice of vice president falls to the Senate. With the House expected to remain in Republican hands, a tie would mean a Romney presidency. Democrats are likely to retain control of the Senate, meaning Vice President Joe Biden would have a second term.
The state of the race:
In 41 states plus the District of Columbia, the results are fairly predictable. States like Texas and Alabama are almost certain to support Romney; California and New York are among those favoring Obama.
An Associated Press tally shows Obama ahead in states with 237 electoral votes; Romney leads in states with 191. If that holds, Obama must win in enough swing states to accumulate 33 more electoral votes. Romney needs 79 more.
The two biggest swing-state prizes are Ohio, with 18 electoral votes, and Florida, with 29. Polls show the candidates running even in Florida, but Obama has a slight lead in Ohio.
Both states are crucial for Romney. If Obama wins in Florida, Romney would need to sweep all the other swing states, including Ohio. If Romney wins in Florida, but loses Ohio, Obama would still be just 15 electoral votes shy of victory. That would leave him with several paths to victory. For example, he could win by taking Nevada (6 electors) and Wisconsin (10), two states where polls show him leading.
Because of those stakes, many analysts see Ohio as the pivotal state on election night. No Republican presidential candidate has ever won the White House without also carrying the Midwestern state.
The other five swing states are North Carolina (15), Virginia (13), Iowa (6), Colorado (9), and New Hampshire (4).
The economy is by far the biggest issue in the race. The United States has struggled to return to full strength after the late 2008 financial meltdown and the Great Recession, which began during Bush's presidency. Obama takes credit for preventing deeper problems and says that the economy, while not ideal, is on the road to recovery and that Romney would reinstate the policies that led to the collapse. Romney says the continued economic weakness demonstrates the failure of Obama's policies and, noting his own record as a successful businessman, says he knows how to stimulate the private sector and create jobs.