When will workers see the fruits of the recently passed Republican tax bill? In just a few weeks, according to the Internal Revenue Service. Last Thursday, the agency released updated tax withholding tables for employers, so that the amount taken out of people’s paychecks aligns with the new law. But some Democrats worry that the Trump administration may game the system by taking less than necessary in withholding, giving workers larger paychecks—for now. Workers would have to pay back the IRS in the next tax filing season, which comes after the 2018 midterms.

As Politico reported earlier this month, the IRS “is under pressure to take as little as possible so people will see big increases in their take-home pay ahead of this year’s midterm elections.” The fact that IRS Commissioner David Kautter is a temporary political appointee, not confirmed by the Senate, has fed these suspicions. “We oppose any attempts by the administration to systematically under-withhold income taxes during the 2018 tax year, knowing that in 2019 taxpayers may find they owe taxes when they were expecting a refund,” Senator Ron Wyden and Representative Richard Neal wrote to Kautter.

In a press conference last week, Treasury Secretary Steven Mnuchin called these suspicions “ridiculous,” insisting that the agency would never fiddle with the withholding system. However, he added that workers would need to use an IRS calculator to ensure that the correct amount of money was being withheld from their paychecks.

The online calculator, which isn’t available yet, would be particularly important for those who itemize their tax returns. Workers would have to input various information about themselves and their pay, and the calculator would spit out an approximation of withholding. The worker would then have to compare with their paycheck to see if they were over- or under-paying. If there are inaccuracies, then they would have to tell their employer. “This will provide [Americans] with certainty so they are neither over-withheld or under-withheld,” Mnuchin said.

In other words, the Trump administration is shifting responsibility from the government to taxpayers. Rather than be held accountable for the accuracy of people’s paychecks, the IRS and Mnuchin are imploring taxpayers to double-check the government’s work—or risk owing hundreds or thousands of dollars in 2019.