Or course no counterfactual study can predict what might have happened had Jefferson not assumed the presidency in 1801. Counterfactual history only works in the short run, sifting a number of likely results from what we know were in the choices of the participants. Every prediction beyond the first few years after an alleged turning point is unsustainable speculation, which does not mean that we should not try our hand at it. Had the election of 1800 ended differently, it is unlikely that the course of American development would have been much altered over the ensuing decade. But in the unpredictable long run, a few key aspects of American life might have changed had the Federalist Party held onto the presidency for another four years. Its domestic authority might have been nil, but a few often-ignored aspects of foreign affairs might have taken distinctive turns. Not that John Adams or whomever else the Federalists put in the presidency would have accomplished much with a hostile Republican Congress and several state governments ignoring every action of the executive branch. Thomas Jefferson would have orchestrated four years of resistance from Monticello, essentially operating a government in exile.
Congress probably would have blocked the Federalists’ proposals for modernizing the army, navy, and militia, as thy did in Jefferson’s first term, and could have prevented any legislative initiative by the Federalists. Where a Federalist president would have made a difference is on the question of slavery in the United States…. Similarly, as the Republicans charged in 1800, the Federalists might have given generous encouragement to the new Republic of Saint Domingue. At the very least, a Federalist president would have extended diplomatic recognition, sending a powerful message that the United States would not act internationally in support of slavery, again forcing the Jeffersonians to come to terms with their position on that divisive issue.