In this year’s State of the Union address, President Barack Obama was clear. He said, “(A) better politics is one where we spend less time drowning in dark money for ads that pull us into the gutter, and spend more time lifting young people up, with a sense of purpose and possibility, and asking them to join in the great mission of building America.”

With that sentence, he reaffirmed what we all know: Voters deserve to know who is trying to influence their elected officials by contributing money. Without knowing who is behind political spending, we cannot make informed decisions, and we lose a critical check on corruption in our moneyed political system.

We applaud the president for speaking out against the wave of “dark money” that has overtaken U.S. elections, and our response is: “We agree. Act now.”

The president should start by issuing an executive order to require federal government contractors to disclose all of their political spending. He has the power to do so.

Dark money is a problem no matter where it comes from, and according to the Center for Responsive Politics, more than 40 percent of the outside expenditures in the 2014 elections were made by groups that did not fully disclose their donors. But dark money is especially troubling when it comes from government contractors. Secret contractor spending implies a pay-to-play culture in which it’s unknown whether awards are going to those best able to play the political money game, or to those offering the most efficient and high-quality product or service.

Such a system has the potential to waste taxpayer dollars and further foster perceptions of government corruption. The government issues billions of dollars of contracts each year, ranging from buying office supplies, to purchasing planes, to repairing roads and bridges, to paying to clean up toxic chemicals and safeguard our air quality. These contracts should always go to those best suited to do the job, not to the companies writing the biggest check for dark money groups to support candidates.

We pay taxes with the trust that those dollars will be used for these public services and needs, and that they will be spent wisely to benefit society. In return, we deserve strict disclosure of political contributions from any company that has done business with the government to ensure we are not doling out tax dollars in response to political largesse.

Public Citizen recently examined the voluntary political disclosure policies of the 15 largest federal contractors.

Public Citizen’s analysis, which included contractors with $129.1 billion due to them in fiscal year 2013, found that just 47 percent of the largest government contractors claim to fully disclose the details of their contributions to 501(c)(4) groups that may be used to influence elections. Just 33 percent fully disclose the details of such payments to trade associations and other 501(c)(6) groups. Just 27 percent fully disclose contributions to both types of groups.

This analysis is important for two reasons. First, it demonstrates that large contractors that do voluntarily disclose the sources of their funding haven’t seen cataclysmic repercussions visit them as a result. Second, it reaffirms that most government contractors do not now voluntarily disclose.

An executive order would be a real start toward a more completely transparent political system in which all contributions are disclosed online in real time to give voters the most reliable information possible.

If the president were to issue an executive order, citizens would be able to see which officeholders are the greatest beneficiaries of government contractor political giving. It would also help the public to feel confident in our elected representatives and head off further perceptions of pay-to-play corruption.

We urge the president to act.

Lisa Gilbert is the director of Public Citizen’s Congress Watch Division. She wrote this for CQ-Roll Call.