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SIDNEY, Ohio - Wrapping up a two-day bus tour through the state -- where he campaigned with GOP stars like Gov. Chris Christie and drew crowds in the thousands -- the Republican presidential nominee is trying to capitalize on recent momentum following his well-received performance in last week's Presidential Debate.

"This is a critical election," Mitt Romney told an electrified crowd of more than 7,000 Wednesday night. "Ohio could well be the place that elects the next president of the United States."

And nothing could be closer to the truth -- Ohio is critical to Romney winning in November.

There's the historical aspect of it -- no Republican has won the presidency without carrying Ohio. But Ohio's 18 electoral college votes make it a game of simple math -- lose them and it becomes difficult to replace.

Since 2004 -- where it proved the decisive state in President Bush's victory over John Kerry -- Ohio has played a critical role in electing the next president.

President Obama soundly defeated John McCain here in 2008. And while polls still show the president leading Romney in Ohio, the former Massachusetts governor and his campaign advisors are heartened by the latest figures -- a CNN poll released Tuesday shows the race tightening with Obama ahead 51 percent - 47 percent, down significantly from the previous month.

Over the coming weeks, Romney will continue to hammer away -- he released an ad last week appealing to Ohio voters by pledging to create 12 million new jobs and revitalize the manufacturing sector. He will also return here at the end of the week to campaign with his running mate Rep. Paul Ryan.

But he could run into strong headwinds -- the president has battered Romney in TV advertising, painting him as a corporate raider and outsourcer of American jobs in a state devastated by the collapse of the American auto industry and manufacturing sector.

And his pledge to fix the economy is muddied here -- the unemployment rate hovers at 7.2 percent, below the national average of 7.8 percent.

Nonetheless, Romney continued to push his economic message, telling voters they just couldn't afford another Obama term.

"The key thing I want people across Ohio to understand and to ask themselves as you go into the voting booth -- as you vote -- is 'Can we really afford the cost of Barack Obama?'" Romney asked the crowd. "And the answer is 'No!'"