I don't think the Republicans would have the audacity to steal this election electronically. There will be massive civil unrest if this occurs. The only way to know if this is a stolen election to look at the
early evening exit polls, about 7-8pm and compare them to the final results. CNN.COM historically has had good early exit polls. Polling firms will adjust their final exit polls at the end of the night. The early evening polls in the Kerry-Bush 2004 election told me that something fishy was going on. From a 2006 article by Robert Kennedy, Jr:
"For its nationwide poll, Edison/Mitofsky selected a random subsample of 12,219 voters — approximately six times larger than those normally used in national polls — driving the margin of error down to approximately plus or minus one percent. On the evening of the vote, reporters at each of the major networks were briefed by pollsters at 7:54 P.M. Kerry, they were informed, had an insurmountable lead and would win by a rout: at least 309 electoral votes to Bush's 174, with fifty-five too close to call. In London, Prime Minister Tony Blair went to bed contemplating his relationship with President-elect Kerry. As the last polling stations closed on the West Coast, exit polls showed Kerry ahead in ten of eleven battleground states — including commanding leads in Ohio and Florida."
Was the 2004 Election Stolen? : Rolling Stone