Both President Obama and Mitt Romney will need to carefully consider how they approach the issue of Medicare in the coming weeks. To be sure, the political climate has grown increasingly favorable for President Obama and the Democrats in the weeks following the Democratic National Convention.

But with the polls nearly certain to tighten in the weeks leading up to election day, it is clear that the senior vote will play a critical if not decisive role in determining the final outcome. Consider the following: in 2010, turnout among Americans over 65 surged and seniors cast more than one out of five votes. This core constituency voted for Republicans by a 21-point margin.

When it comes to Medicare, both sides are struggling to own the debate. But Medicare Part D is a huge positive for candidates willing to embrace it and has been under discussed on the campaign trail up to this point.

A new poll sponsored by Medicare Today found that 90 percent of seniors are satisfied with Medicare Part D - up twelve points from 78 percent in 2006.

The poll found that both Democrats and Republicans equally favor the program - with respondents saying they are happy with the value, costs, and convenience provided by their coverage.

The poll also found palpable levels of concern about what would happen if Medicare Part D were to be eliminated. 84 percent said that out-of-pocket drug costs would be higher, 61 percent believe they would be unable to fill all of their prescriptions, and 53 percent said they would be more likely to cut back or stop taking medicine altogether.

This year, three of the top five heavily senior populated states (Florida, Pennsylvania and Iowa) are up for grabs, and neither side can afford to sacrifice the critical voting bloc of Americans over 65 - who comprise 13 percent of the population.

And the results to a September survey by the Washington Post/Kaiser Family Foundation "Health Care, Medicare and the Election: A View from Three Swing States - Virginia, Florida, and Ohio" indicate that swing voters are very concerned that the fiscal cliff debate, while unlikely to take center stage until after the election, by all accounts will result in changes to programs that seniors rely upon.

Indeed, clear majorities of voters in Virginia (73 percent), Florida (74 percent), and Ohio (78 percent) indicated that they would like to see policymakers reduce the federal budget deficit without reducing Medicare spending.

The Obama campaign has repeatedly defended provisions in the Affordable Care Act that cut Medicare spending by $750 billion as nothing more than closing loopholes and limiting payments to providers. The Romney campaign, while still defending itself against comments that 47 percent of the American people are "victims" and rely on government programs (seniors are very much part of this number), have made a point to label the White House's actions as "raiding" Medicare to pay for Obamacare.

Despite being a target for Democrats in the past, taking on the program known as Medicare Part D carries a significant amount of political risk that the Obama campaign cannot afford as both sides prepare to make their closing arguments.

Mitt Romney's selection of Paul Ryan as his vice presidential running mate immediately put Medicare on the front burner and Democrats on the offensive, especially in Florida with recent gains among seniors.

And needless to say, given the concerns that have been raised about the impact the Ryan plan potentially will have, Republicans also need to take particular care not to appear to question an extraordinarily popular program that was, after all, proposed and passed by a Republican President and Republican Congress.

Douglas Schoen is a political strategist and author of "Hopelessly Divided: The New Crisis in American Politics and What it Means for 2012 and Beyond," published by Rowman & Littlefield Publishers.