During this election season, we can add one more certainty to life in addition to death and taxes: Democrats will maintain control of the House and Senate.

Republican retirements in the House and the number of competitive GOP seats in the Senate ensure that Democrats will continue to lead Capitol Hill until at least 2011.

That means that Democrats will advance their agenda, Republican filibusters in the Senate notwithstanding, in two ways: through legislation and oversight.

Corporate executives experienced the latter on March 7. At a hearing of the House Oversight and Government Reform Committee, panel Democrats grilled three current and former financial firm leaders on what they believe is the incongruity of their generous pay packages at a time when the subprime mortgage meltdown is roiling the economy.

It was the second oversight committee hearing on executive pay in three months. A previous session focused on alleged conflicts of interest in pay consulting. Democrats are trying to make the political point that executive remuneration is out of whack with the economic struggle most of their constituents face.

The atmosphere for the latest hearing was made more uncomfortable for the executives by a majority staff report released the previous day.

It included e-mails from Angelo Mozilo, founder and CEO of Countrywide Financial Corp., to the Countrywide board regarding an executive compensation specialist he hired as his own representative as well as an exchange about his wife’s usage of a corporate jet.

During the hearing, Democrats pressed Mozilo for answers about those messages. They also demanded from Richard Parsons, chairman of Time Warner and chairman of the personnel and compensation committee at Citigroup, an explanation of why Charles Prince, former chairman and CEO of Citigroup, received a $10 million bonus on his way out the door last year.

On that point, the politicians had the upper hand. Del. Eleanor Holmes Norton, D-District of Columbia, bored into Parsons. She wanted to know whether the Citigroup board had in fact only spent 20 minutes deliberating about the bonus.

Parsons was no match for Norton. He tried to explain that Prince’s base salary was $1 million. Citigroup would then routinely add a bonus to make his pay more competitive with prevailing rates in the financial industry. His deliberate response lacked the drama that Norton conveyed in posing the query.

Rep. Elijah Cummings, D-Maryland, also made a visceral point about how his constituents face threats to their homes while the CEOs earned tens—or hundreds—of millions of dollars. “Something doesn’t smell right,” Cummings said.

And that’s the point of oversight. The committee has very little legislative jurisdiction. So, it won’t produce an executive pay bill. But the panel can air its grievances and apply moral suasion to any issue it chooses.

By doing so, it might build momentum for legislation introduced by other committees, like a bill that would allow shareholders to vote on executive pay packages.

Or the heat produced by oversight might forge changes in corporate practices. “The bottom line is there needs to be better … accountability” from executives to avoid “economic disruptions,” said Rep. Henry Waxman, D-California and chairman of the oversight committee.

Republicans assert that the committee shouldn’t be meddling in corporate affairs. They say that Democrats are simply scoring political points and providing discovery for potential lawsuits.

Corporate leaders may agree. But if the Democrats stay in power—and they will—the business community had better find a way to address the party’s concerns about executive pay. Otherwise, they should prepare to be hauled up to Capitol Hill for more prickly hearings.