Elections are about numbers, and right now the president's are bad. To understand why, consider 2008 as a reference point. That year, Barack Obama received 69,456,897 votes to John McCain's 59,934,814.
But a big chunk of President Obama's 9.5 million-vote advantage is probably gone. Let's break this down. According to exit polls, 44.8 million Republicans showed up to vote in 2004 while only 41.4 million did in 2008. Almost all those 3.4 million Republicans who stayed home have been energized by Mr. Obama's agenda and are now eager to vote against him.
Gallup found in April that Republicans were five points more likely to vote than Democrats. More recent measures, including by the Pew Research Center in June, show Republican voters displaying more intense interest than Democrats. If 2008 stay-at-home Republicans vote, Mr. Obama's margin would shrink by more than one-third (to 6.1 million). Similarly, the 2.4 million veterans who voted in 2004 but did not in 2008 could turn out in 2012. Mr. McCain's winning margin among vets was 10 points.
Nor can Mr. Obama count on winning the support of 9% of Republicans—or roughly 3.7 million—as he did in 2008 (according to exit polls). If he instead wins the same 6% of Republicans as Sen. John Kerry did in 2004, then 1.25 million Obama Republicans would be subtracted from the president's column and added to Mr. Romney's. That would narrow Mr. Obama's popular-vote margin to 3.6 million.
According to the exit polls, Mr. Obama won independents by eight points in 2008 (52% vs. 44% for Mr. McCain). But the July 1 CNN/Opinion Research poll showed Mr. Romney winning independents by seven points, 49% to 42%. The June 24 Gallup poll found Mr. Romney up by one among independents, 43% to 42%. Independents will shift back and forth, but if they split 49% to 49% (with the rest going to minor candidates), then Mr. Obama's vote total would be shaved by 1.1 million and Mr. Romney's would grow by an equal amount, cutting the president's margin to 1.4 million.
Among voters age 65 years or older, Mr. Obama lagged behind Mr. McCain by eight points, 45% to 53%. That margin has doubled to 16 points (41% vs. 57%) in the July 1 CNN/Opinion Research. In the June 24 Gallup, the gap among seniors is 15 points, 39% to 54%. A big gap in November implies that Mr. Obama would lose some undetermined number of Democratic or independent seniors.
Mr. Obama also has a problem with middle-class voters. In the June 24 Gallup, he led among those making up to $36,000 a year by 51% to 39%, and he trailed among those making $36,000-$90,000 by 44% to 51%, both well behind his 2008 pace.
Finally, Mr. Obama faces real challenges in generating the turnout he needs from blacks, Hispanics and young people.
If the turnout of African American voters this fall is just a half-point less than in the last election, Mr. Obama would lose roughly 700,000 votes. With black unemployment at 14.4%, that's a real possibility.
Mr. Obama captured Hispanics by 67% to 31% in 2008. But the June 24 NBC/Wall Street Journal/Telemundo poll found Latino "interest in this election remains far below 2008 levels." Even after Mr. Obama's June 15 decree exempting young illegal immigrants from deportation, his approval rating among Hispanics is down to 58%. In the June 25 Gallup poll, four in 10 Hispanic voters list unemployment and economic growth as their greatest concern. This is no surprise, since Latino unemployment is 11%, according to the Bureau of Labor Statistics.
Another group vital to Mr. Obama's 2008 victory—young people—are now less enthusiastic about voting and about Mr. Obama. According to a June 24 NBC/Wall Street Journal poll, Mr. Obama leads Mr. Romney among them by 23 points—11 points less than Mr. Obama's margin over Mr. McCain. If this holds up, it would cost Mr. Obama up to 1.25 million votes.
Still, Romney isn't home free. To win 270 Electoral College votes, he will have to keep Republicans energized, increase his support among independents, seniors and the middle class, and make inroads among Hispanics and young voters. To do that, he will need to do much more than just criticize Mr. Obama's many failures.
The closer Nov. 6 gets, the more pressure there will be on the GOP challenger to offer a principled, practical, detailed governing vision. He has many important policies on his website. He could cite them more consistently in his speeches and point voters to them in his campaign ads.
That doesn't mean rolling out everything right now. If Team Romney were to do that, the media will declare it old news by Labor Day. But to close the sale, Mr. Romney needs to be perceived on Election Day as the man with a plan.
This article originally appeared on WSJ.com on Wednesday, July 11, 2012.