WASHINGTON — This year’s Senate races have featured astronomical spending, ceaseless attack ads and innumerable slaps at a president who’s not on the ballot. Largely missing, however, are ideas on how best to govern the nation.

Even with control of the Senate at stake, serious discussions about deficit spending, climate change, immigration, Social Security’s long-term future and other knotty issues rarely emerged.

Republicans overwhelmingly devoted their campaigns to criticizing President Barack Obama’s leadership and governing style. And Democrats, while sometimes forced to wanly defend “Obamacare,” often caricatured their opponents as throwbacks eager to limit women’s reproductive rights.

To be sure, superficial debates and 30-second attack ads have fueled U.S. political campaigns for years. But even by that measure, political veterans said, this fall’s elections were remarkably light on policy and ideas.

“I’m struck by how not any of the significant issues that Congress has to deal with — immigration, infrastructure, a grand bargain on taxes and spending — are playing out in this election,” said Steve Elmendorf, a former top Democratic congressional aide.