In a political landscape where a major party's presidential nominee dropping out during the general election campaign has never occurred, looking at rare instances of candidate switches at the statewide level may offer some insights into the potential fallout of a Joe Biden withdrawal. While not directly comparable, two notable cases from 2002 shed light on the challenges, opportunities, and risks involved.

The first case unfolded in New Jersey, where Senator Robert Torricelli faced a federal investigation regarding allegations made by a donor. Despite being cleared of charges, the Senate Ethics Committee's admonishment in July intensified the scrutiny on Torricelli. By Labor Day, his Republican opponent, Doug Forrester, had pulled even in the race. A court order in late September allowed the release of a memo supporting the allegations, leading to mounting pressure for Torricelli to step down.

With just five weeks until the election, Democratic leaders in New Jersey sought an emergency replacement. After encountering initial reluctance from potential candidates, they secured the agreement of former Senator Frank Lautenberg, a familiar figure to the state's citizens. The swap faced criticism from Republicans, but polling indicated that voters were disenchanted with Torricelli, not the Democratic Party as a whole. Lautenberg ultimately won the election by a 10-point margin, preserving the Democrats' single-seat Senate majority.

The second case unfolded tragically in Minnesota, where Senator Paul Wellstone, a beloved figure among liberals, tragically died in a plane crash just over a week before the election. Both parties acknowledged the need for sensitivity amid widespread grief, and the Republican nominee, Norm Coleman, temporarily suspended campaigning. However, Democrats needed to secure a new candidate's placement on the ballot. Party leaders, along with Wellstone's family, expressed a preference for former Vice President Walter Mondale. An October poll showed Wellstone leading by six points, and subsequent polling indicated that Mondale held an eight-point advantage.

Despite the expectation that Mondale would enter the race, he remained silent, respecting a period of mourning and refraining from public comments prior to Wellstone's memorial service. However, the service itself became somewhat politicized, with some speeches veering into partisan territory. Rick Kahn, a close friend and volunteer campaign treasurer of Wellstone, urged the crowd to win the upcoming election on Wellstone's behalf. The memorial service received mixed reactions, with Republicans accusing Democrats of exploiting the event.

Ultimately, the advantage initially assumed for Mondale eroded, and Coleman emerged victorious in a tight race, prevailing by a two-point margin. These instances highlight the complex dynamics involved in candidate switches, including the potential for a shift in public sentiment, the need for swift action by party leaders, and the political backlash that may ensue.

While these cases may not directly parallel a hypothetical Biden withdrawal, they provide historical context for the challenges and opportunities that would arise. As the presumptive Democratic nominee, Biden's potential withdrawal would mark uncharted territories in U.S. presidential elections, adding uncertainty to an already turbulent electoral landscape.