Voters have seen John McCain and Barack Obama debate twice before, but the stakes have never been higher for either candidate than they are for tonight’s third debate at Hofstra University. Here are five things to watch for during tonight’s debate on economic and domestic issues.

1). Micro vs. Macro – The economy should dominate this debate tonight, and while Barack Obama has maintained a laser like focus on the economy, the McCain campaign is still trying to find their message. The difference thus far between the two candidates has been Obama’s ability to connect with voters and talk about the economy on the micro level. Obama talks about jobs, gas and food prices, education, retirement. He has been talking about the issues that people are sitting at home every night worrying about.

McCain has struggled mightily to connect with voters on a personal level about the economy. He is stuck repeating the conservatives ideological mantra of tax cuts. The problem is that voters aren’t buying the tax cut argument after George W. Bush campaigned on and implemented the same policy that McCain is advocating. I expect both candidates will discuss their recently unveiled economic plans, but Obama will continue to focus on the middle class.

2). Aggressiveness – Debates are often won and lost based on the personal perceptions of the people watching. Sometimes, how something is said is more important than what is said. McCain is supposed to be the experienced candidate, yet he has been nervous and overaggressive in the first two debates. His combative style has not made a favorable impression on voters. This is evidence by the fact that McCain’s approval ratings drop after each debate. McCain reminds me of Bob Dole. He doesn’t have a personality that people like. This combined with his tendency to exhibit a mean streak and be overaggressive are reasons why voters think that Obama won the debates.

In contrast, Obama’s cool measured style, which was a concern of many Democrats, has worked to his benefit so far in these debates. Obama looks like a man who can handle the economy, while McCain seems like he would rather be talking about something else. It is unrealistic to expect McCain to reinvent himself, but he needs to be aggressive on the issues, not towards Obama, who is in control of this race, and only needs to continue what he has been doing.

3). Taxes – The McCain campaign has been making the argument that Barack Obama is a tax and spend liberal, but it is hard to make this charge stick when Obama keeps putting out plans that cut taxes. The bigger problem for McCain is that voters don’t see the tax cut argument as an economic solution. If McCain sticks to attacking Obama on taxes, he will lose this debate. McCain needs to let go of the tax cut argument, and start talking kitchen table politics. However, I suspect that he will continue to hammer away at the pointless tax cut argument.

For his part, Obama has been able to turn McCain tax cut argument into a discussion about tax burden and class. He reverses McCain’s own argument on him, by appealing to the populist idea that people ought to pay their fair share, then he attacks McCain’s plan as taxing the rest of us to give to the rich. This has been a highly effective argument, and if McCain is dumb enough to argue about taxes again, Obama will hit him with this.

4). Health Care – I expect McCain to call Obama’s plan universal health care, but the problem the Republican faces is that he has been unable to defend two charges that Obama has made about his own health care plan. Obama has charged that the tax credit McCain promises doesn’t go to the individual to buy health care, but to the insurance companies, and Obama has also made political hay by pointing out that McCain wants to tax health care benefits.

The charges that Obama has made against McCain’s plan are true, and so far, McCain has not tried to refute them in the first two debates. McCain has to be more vigorous in defending his own plan. He has yet to tell America why he thinks that his plan is better than Obama’s. I have no reason to believe that he will do this tonight. Obama has the better personal story on health care, and the better plan. It will be interesting to see if McCain even tries to defend his.

5). To Ayers Is Human – In the first two debates, McCain did not attack Obama’s character by bringing up William Ayers or Rev. Wright. There is a split in the McCain campaign over whether or not he should go after Obama’s character in this way. McCain is trailing by double digits in almost every poll, and he might be tempted to take the gamble and launch a full blown assault on Obama’s character tonight. The danger in this risk is that if it backfires, it very well could finish his campaign.

The other aspect of this is that the Obama camp desperately wants McCain to bring up Ayers and Wright. They want a chance to address these smears in front of John McCain on national television in the worst way. I personally don’t see what has to gain by bringing up Ayers and Wright tonight. By bringing up Ayers, McCain would providing Obama proof that McCain is running a campaign based on distractions not the issues.

These charges about Ayers and Wright are nothing new, and I suspect that voters will punish McCain for bringing them up, and not talking about the economy. The reason why McCain is poised to lose this election is that he has been running non-issue oriented campaign in an issue oriented year. McCain has one last chance tonight to right the ship and talk about the issues. He would be making a fatal mistake if he decided to say anything that distracted from the discussion of the economy. The truth is that most people want to vote for Obama, and unless he makes the big mistake, the polls will say that he won this debate too.