(CNN) -- Sen. John McCain on Friday blasted both the Bush administration and the Obama campaign for not doing enough to help homeowners stay in their homes as he began a two-day bus tour across the must-win state of Ohio.
With just four days until Election Day, McCain's tour begins the same day that his Democratic rival, Sen. Barack Obama, returns to Iowa, the state that was the springboard for his presidential campaign.
A CNN poll of polls calculated Wednesday has Obama leading McCain 50 percent to 43 percent, with 7 percent unsure. The poll of polls is an average of eight surveys.
At the first stop on his bus tour, McCain touted his plan to use a portion of the $700 billion financial bailout package passed by Congress to buy up the mortgages of distressed homeowners so they can "stay in their homes."
"That's the American dream, and I'm going to protect it," McCain told supporters in Hanoverton, Ohio. "This administration isn't doing enough."
McCain also accused Democrats of trying to scare voters on Halloween by saying that he would take away Social Security and Medicare.
"My friends, our Americans have wised up," he said. "I'm going to protect Social Security. I'm going to protect Medicare, and I'm not going to let this Congress tax away your retirement savings."
McCain later plans to hold rallies in Steubenville, New Philadelphia and Columbus, Ohio. California Gov. Arnold Schwarzenegger will join McCain on Friday night during the rally in Columbus.
The Arizona Republican must win Ohio's 20 electoral votes to have any chance of becoming president, and recent polls suggest that McCain is going into the campaign's final weekend behind in Ohio.
The CNN poll of polls in Ohio calculated Wednesday indicates that Obama has an 8-point lead in the state, with the Illinois senator ahead of McCain 50 percent to 42 percent, with 8 percent unsure.
No Republican has ever won the presidency without winning Ohio.
Despite being behind the polls, McCain on Friday expressed confidence that the tide was turning in his favor.
"I want to tell you the enthusiasm and the momentum that I feel here in Ohio is going to carry us to victory here in Ohio and throughout this country," McCain told supporters in Hanoverton.
The Republican nominee will not spend all of his final weekend campaigning on serious matters. McCain plans to make an appearance on Saturday Night Live. He has appeared on the show before, but this weekend will be his first appearance this year.
Obama on Friday will return to the state that gave him his first significant win in his quest for the presidency: Iowa.
In January, Obama scored an upset victory by capturing 38 percent of the vote in the Iowa caucuses, topping both John Edwards and Sen. Hillary Clinton, who was at the time considered the front-runner in the Democratic presidential context.
Partially due to the support he developed during the caucuses, Obama has maintained a commanding lead in Iowa throughout the general election season. The latest CNN poll of polls in Iowa shows Obama leading McCain by 12 points, 52 percent to 40 percent.
Obama will hold a rally in Des Moines, Iowa, then head to Indiana, where he is in a tight race with McCain. A CNN poll of polls has McCain slightly ahead, 47 percent to 46 percent, with 7 percent unsure.
The two vice presidential nominees are also campaigning in battleground states Friday. Alaska Gov. Sarah Palin, the Republican vice presidential pick, started her day by meeting voters in Latrobe, Pennsylvania. She will later travel to York, Pennsylvania.
Her Democratic counterpart, Sen. Joe Biden, will start the day at a rally in his home state of Delaware then head to events in Kettering and Lima, Ohio.
Recent polls shows that the Republican ticket also has ground to make up in Pennsylvania. A CNN poll of polls calculated Wednesday has the Obama-Biden ticket leading the McCain-Palin ticket 53 percent to 42 percent with 5 percent undecided.