If McCain wins in November but Democrats increase their majorities in Congress, WHAT does THAT mean?

[Proud Liberal Dem]

I hate writing posts like this because, frankly, the thought of McSame SOMEHOW eking out a win in November REALLY frightens and depresses me but I'm confused about the polling (if it is to taken at face value).
Polls clearly indicate that the race between Obama and McSame to be very close and some polls also suggest a higher level of confidence (although I don't know how) in McSame on a lot of issues, particularly national security.
However, the polling data indicates that voters prefer Democrats over Republicans this year and the policies we are promoting while Republicans are still pushing the same failed Bush policies that have harmed and weakened our country. As such, it has been reasonably predicted that we are likely to not only maintain our hold on Congress but actually increase it.
So, my question of the day is, what kind of "signal", message, etc. would voters (assuming the results end up being accurate-which, of course, is "iffy") be sending by electing McCain POTUS but keeping Democrats in control of Congress and what would that mean for our party? A majority of voters may, unfortunately, end up seeing McCain, either because of racism, ignorance, and/or other factors, as being the "safest" (or less "risky") choice for POTUS but what do they expect him to do for the country in terms of domestic issues (MANY OF WHICH HE HAS ADMITTED HE KNOWS LITTLE OR NOTHING ABOUT) and how would McSame be able to "reach across the aisle" to work with Democrats after what has ALREADY been a nasty campaign (for that matter, how in the hell did people think Bush would work well with the Democrats after Florida 2000 and especially after the "swiftboating" of John Kerry in 2004)? What would the Democrats be able to achieve without Obama as POTUS and WHY would a majority of voter want MORE gridlock instead of change when most people seem to believe that we are on the "wrong track" in this country?