After all the fundraising, political ads, rallies, meetings and get-out-the vote efforts, a few counties in just one state - Ohio - could have an outsized say in the outcome of Tuesday's presidential election.

At a national level polls show President Barack Obama and Republican rival Mitt Romney tied. Under most calculations, Ohio is currently the most critical battleground in the candidates' state-by-state race to capture the 270 electoral votes needed to win the White House.

A Reuters/Ipsos poll on Sunday showed Obama leading the former Massachusetts governor 48 percent to 44 percent in Ohio. Other polls show a similar tight race in the Midwestern state of 11.5 million people.

Obama won the state by 4.6 percentage points in his defeat of Republican John McCain in 2008.Here is what election analysts say the campaigns need to do to win longtime swing state Ohio and its 18 electoral college votes.
Read the report on Reuters.