On July 29, 2004, Sen. John Kerry, D-Mass., came out of the Democratic National Convention with a slight lead over President George W. Bush in national presidential polls. But throughout the month of August he was put on the defensive by ads released by the Swift Boat Veterans for Truth, who questioned his military record in Vietnam. By the time Bush accepted the Republican nomination in early September, Kerry had relinquished the lead, and he would never regain it.

Without relitigating the 2004 election or revisiting the Swift Boat issue, it's worth questioning whether we could be seeing a repeat of this episode in the current election, with President Obama unleashing a wave of attacks against presumptive Republican nominee Mitt Romney's business career at Bain Capital.

What made the Swift Boat attacks effective was that Democrats had nominated Kerry in large part because they thought his military service would make him a more credible critic of the Iraq War. The Swift Boat attacks undermined this purported strength. Likewise, during the current campaign, Romney was able to overcome criticism of his conservative credentials and win the Republican primary by arguing that his successful business background put him in the best position to campaign on the economy. The Bain attacks are aimed at obliterating this advantage.

The Obama campaign's charges against Bain initially focused on companies that were taken over by the private equity firm and later shed jobs or moved some operations overseas. But examples being given by the Obama team came after Romney left Bain in February 1999 to run the 2002 Salt Lake City Olympics. The Obama campaign then seized on reports by liberal websites Mother Jones and Talking Points Memo -- and later by the Boston Globe -- citing Securities and Exchange Commission filings that listed Romney as the CEO of Bain after he was said to have left for the Olympics. Stephanie Cutter, Obama's deputy campaign manager, took the charges to a new and absurd level when she suggested on a Thursday conference call with reporters last Thursday that Romney may have committed a felony with those filings.

The idea that Romney was actively involved in managing Bain's day-to-day operations while turning around an Olympic Games that had been embroiled in scandal and debt isn't remotely credible. In a statement last week, Bain Capital backed up Romney and explained that, "Due to the sudden nature of Mr. Romney's departure, he remained the sole stockholder for a time while formal ownership was being documented and transferred to the group of partners who took over management of the firm in 1999. Accordingly, Mr. Romney was reported in various capacities on SEC filings during this period." This was further corroborated by Fortune magazine, which uncovered a June 2000 offering for a new Bain private equity fund that listed 18 managers, none of whom were Romney.

Though Obama's attacks on Romney's Bain record are overblown and of little merit, it doesn't mean they'll be politically ineffective. Last week's debate was almost entirely focused on Romney's Bain record instead of the deteriorating economic picture -- and this was after the recent dismal jobs report showing unemployment at a stubbornly high 8.2 percent.

Romney must figure out how to respond to Obama's assault on his career at Bain. Otherwise, he will join Kerry as one more Massachusetts politician who lost to a vulnerable incumbent president.