President Obama isn’t apologizing. Rather than backing away from discredited charges about Mitt Romney outsourcing jobs and attacks about his wealth, the president doubled down on the mud slinging in the past few days. With the economy remaining in the doldrums and no prospect of improvement before November, the president has proposed no new ideas for its revival other than another hike in federal spending. So rather than running on his accomplishments, such as they are, the president is concentrating on discrediting his opponent and appealing to his political base.

In doing so, the president appears to be following the model established in 2004 when President Bush faced a tough re-election fight against a plausible but not very compelling opponent in John Kerry. Bush never personally engaged in the sort of vitriol that Obama routinely engages in (Bush was too conscious of the dignity of his office and such conduct also went against the grain of the nice-guy persona that was key to his appeal). The focus of his re-election effort was the push to increase the turnout of conservatives and evangelicals that enabled him to win a close race. Though the Democrats won’t admit it, they are hoping this Karl Rove-inspired formula will be just as successful for them. But while his liberal base has been begging Obama to get nastier since he took office, it remains to be seen whether a man who was catapulted to office by lofty rhetoric about “hope” and “change” can remain in it by wallowing in political mire. Nor does it alter the fundamental question that any incumbent seeking re-election must answer about whether the nation’s fiscal health has improved on his watch.

With the polls showing the race a virtual dead-heat, there is little likelihood of either candidate pulling away. Nor is there any great mass of undecided voters whose more moderate views would make a swing to the left imprudent. Thus, Obama’s decision to pursue the decidedly unpresidential route of sliming his opponent makes some political sense. His only hope of victory is to energize a liberal base that is decidedly less enthusiastic than it was four years ago. To do that, he must feed them what they want to hear: class warfare and attacks on Romney as a wealthy plutocrat.

Thus, not only will Romney not get any apologies for the president recycling canards about his business career, he can expect it to only get worse with Democrats. That ought to concern Republicans who fear an all-out assault by the president will define his opponent and turn his personal record of success into a liability. One shouldn’t underestimate the power of negative attacks, but there are two reasons why a repeat of the GOP’s 2004 tactics may fail.

First, is the difference between Romney and Kerry. Like the 2004 Democratic nominee, Romney may be a wealthy man, but unlike Kerry, he built his own fortune rather than marrying into wealth. He is not a natural politician and doesn’t connect well with the voters. But neither is he a passive aristocrat who acted as if he was entitled to the nation’s highest office, as Kerry often did. While Kerry gave the appearance of a stationary target, Romney is a clever man who will not willingly play the role of tackling dummy for the Democrats.

The second difference is that the country is in a very different position than it was in 2004. Eight years ago, the Iraq War was starting to look like a mess, but the economy was not in crisis the way it is today. More Americans had voted for Bush’s opponent in 2000, and even his response to the 9/11 attacks had not reconciled Democrats to his presidency, so he was in for a tough fight in 2004 no matter what he had accomplished.

By contrast, today Obama still has the advantage of being a historic president with the bulk of the press in his pocket. But with the state of the economy the only issue anyone is talking about, the president’s belief that he can avoid blame by pointing the finger at his predecessor may be mistaken.

The problem with political science is that it is not science. Each election is different. If the president’s campaign and its unpleasant tactics can generate a big turnout from the left, the president may yet prevail. But the circumstances of 2012 are not those that allowed the Bush campaign to run to the right with impunity in 2004. The harsh economic reality that is leading to a steady stream of bad economic news may render the Karl Rove formula moot.