(CBS News) BOSTON -- Polls show Mitt Romney's path to the White House may be narrowing.
The best chance for the Republican standard bearer to turn the tide may be Wednesday's first presidential debate.
With the stakes incredibly high, both candidates have begun preparing for the big night.
Saturday was expected to be a quiet day for both President Obama and Romney.
Neither candidate has any public events planned.
But behind the scenes, they were to cram for that first debate.
Some Republican strategists say if Romney doesn't do well, it could be downhill from there.
But the president's campaign is also worried -- concerned he could make a high-profile mistake, giving Romney the opening he needs.
At campaign appearances Friday, Mr. Obama and Romney seemed to be previewing the first debate, when the battle over taxes is expected to take center stage.
The president told a crowd, "My opponent thinks it's fair that somebody who makes $20 million a year like he does pays a lower tax rate than a cop or a teacher who makes $50,000."
Romney says he'll hold the president accountable for misrepresenting his record.
"I will not raise taxes on middle income Americans," he insisted at one stop.
The stakes in the debate are so high that both candidates will soon retreat into political cocoons to get ready.
On Sunday, Mr. Obama will begin three days of intensive preparation in Nevada. And on Monday, Romney will hunker down for two days in Denver, the site of Wednesday's debate.
In Romney's sessions, Mr. Obama will be played by Ohio Sen. Rob Portman, who was on Romney's short-list for vice president. On stage with the president will be Mass. Sen. John Kerry, playing Romney. Kerry and Romney knew each other well when Romney was governor of Massachusetts.
Both campaigns are desperately trying to lower expectations.
In a memo leaked to the press, a top Romney adviser called the president "one of the most talented political communicators in modern history" and noted that he has engaged in eight one-on-one presidential debates, while this is Romney's first.
The Obama campaign is also trying to downplay expectations, saying he's had little time to prepare for the debates because he's been so busy as president dealing with a series of crises in the Middle East.