The midterm elections are over. Finally. What does that mean? Well, no more commercials, for one thing, but it also might (and the contingency of this prediction cannot be emphasized enough) mean a slow return to fiscal sanity. Historically, budgets tend to stabilize, and deficits tend to shrink, when government is divided. It has been a long time since we have had divided government characterized by one party with a socialist wing and the other with a trillion-dollar infrastructure plan, but historical trends may yet return to force nevertheless.

For all their talk about keeping budgets in check and maintaining fiscal sanity, both major political parties in the United States tend to rack up massive debts when they control both lawmaking branches of the federal government. It is under divided government, rather — when one party controls one or both chambers of Congress and the other controls the White House — that budgets tend to shrink, and deficits begin to fall.

The correlation is not perfect, of course. Many other factors affect government spending levels. If the economy is in recession spending levels spike regardless of the distribution of political power, and during wartime, spending trends follow mobilization to fight the conflict. What tends to be true, though, is that when the opposition party controls Congress, specifically the power of the purse in the House of Representatives, the rate of change in the federal deficit goes negative.

Take the Republican takeover of Congress during the administration of President Obama as an example. President Obama began his first term with Democrats in control of both the House and the Senate. Under this unified government, spending exploded in the first year in which the Obama administration was completely in control of the budget (FY 2010, see chart below). Although, again, it must be noted that much of this spending was in the form of fiscal stimulus, in an attempt to counteract the deepening Great Recession, and that spending did start to come down after President Obama’s first budget (it is hard not to come down when the deficit was nearly $900 billion larger in FY 2010 than FY 2009).