Barack Obama and Mitt Romney hold their first debate tonight at the University of Denver, and by some estimates it may be Romney's best and last chance to shake up the race and overtake the president.
There are only three big, predictable events in a presidential campaign — the vice presidential pick, the convention and the debates — that can give a candidate a jolt of momentum. The first two opportunities did little or nothing to help Romney, and 30 states are already voting.
That could make for a thrilling 90 minutes in Denver, as the president and challenger are side by side for the first time.
Or not. Few debates actually end up significantly altering a presidential campaign, and more often than not they are easily forgettable. Anyone remember a key moment in the John McCain-Barack Obama debates in 2008?
Romney and Obama are competent, smart men who have been practicing their answers, memorizing witty retorts and studying endless debate scenarios to make the most of the night and avoid gaffes.
Here are five things to watch:
1 Body language. Sometimes it's not what's said that matters most, but what viewers actually see on their TV screens.
In the first televised presidential debate, Richard Nixon famously looked pale, dour and sweaty in 1960 beside the youthful and telegenic John F. Kennedy. George H.W. Bush in 1992 fed the sense that he was disconnected from regular people when he conspicuously looked at his watch while an audience member asked a question. Al Gore on substance probably won a 2000 debate with George W. Bush — but as people focused on his sighs and annoyed reactions, he looked increasingly like an arrogant, know-it-all.
2 Aggressive or cautious? Obama is narrowly or comfortably leading in all the battleground states and has every incentive to play it safe and focus on avoiding mistakes. A boring evening only helps him.
On the other hand, Democrats who studied Romney's 20 Republican primary debates this cycle know that his weakest moments often came when rivals aggressively challenged him. "I'll bet you $10,000," he snapped when Texas Gov. Rick Perry went after his Massachusetts health care plan.
Obama is famously measured, but he is also a fierce competitor who has shown contempt for Romney's rhetoric and agenda. It's no sure thing he plays it safe against the former Massachusetts governor.
As for Romney, Newt Gingrich can attest to how effective and aggressive he can be in debates when they truly matter. The president with a humility deficit is unaccustomed to being challenged directly and Romney has every incentive to try to knock Obama off stride.
Obama's advisers surely have warned about his potential for coming off as a condescending lecturer.
"You're likable enough, Hillary," he sniffed to rival Clinton in a 2008 debate, and wound up losing the New Hampshire primary.
3 Time limits. This is not a standard debate where the candidates are restricted to two-minute answers. The debate instead will be divided into six, 15-minute sections, allowing more free-wheeling discussion and back and forth.
Hopefully that makes for a more interesting and less-scripted evening, particularly since moderator Jim Lehrer, after 11 previous debates, knows what he is doing. It also should make the Obama campaign anxious: Even by Washington standards, Obama can be extraordinarily long-winded, rarely saying in less than eight minutes what could be said in 90 seconds.
4 Specifics. Neither Obama nor Romney has laid out much detail about what they intend to do over the next four years as president. Instead, they have talked about broad goals — more energy independence, reduced deficit, more trade.
If Romney over 90 minutes still can't name a single tax deduction he would eliminate to pay for his tax cuts, and Obama can't outline a credible plan to rein in entitlement spending, it could create some awkward moments before millions of television viewers.
5 47 percent. Two weeks ago came the leaked videotape of Romney at a closed-door South Florida fundraiser saying 47 percent of Americans "are dependent upon government" and "believe that they are victims" and inevitably vote for Obama.
A Tampa Bay Times/Bay News 9/Miami Herald poll showed little impact in Florida in the immediate aftermath, but since then "47 percent" has sunk into America's political lexicon. A Pew Research Center poll released this week found two-thirds of Americans are aware of the remarks, and 55 percent have a negative view of them.
Obama is airing blistering ads about the comments in battleground states, including Florida. Romney is ready to be attacked on them in Denver.
The question is whether the multimillionaire former venture capitalist can respond in a way to reassure people that he does in fact have some understanding and empathy of middle-class Americans.
If that doesn't work, they have two more debates: Oct. 16 and Oct. 22.
Adam C. Smith can be reached at email@example.com.