Almost daily, congressional Republicans and Trump administration officials tout evidence that workers are seeing more take-home pay as Washington adjusts its tax-withholding tables; and that companies, flush with cash after the plan’s huge reduction in corporate taxes, are providing bonuses and other financial benefits to their employees. Americans for Prosperity, the political group associated with the billionaire Koch brothers, earlier this month aired a flight of television ads criticizing Democratic Senators Claire McCaskill of Missouri and Joe Donnelly of Indiana for voting against the plan.

Recent polls have provided Republicans some indication that their campaign is working. When the tax bill passed in December, surveys showed that most Americans opposed it. But the plan has gained ground since. An online SurveyMonkey/New York Times poll in early February was the first to show the tax plan drawing support from half of Americans. That’s still an equivocal verdict. But the trajectory shows that, in the short term, Republicans—and their business allies—have been winning the tax debate. If Democrats can’t reverse that trend, it could limit their gains this fall.

Democrats are only starting to engage with the Republican case for the tax bill. They showed their cards most clearly in the ads a Democratic group recently ran to defend McCaskill and Donnelly. In those spots, the Senate Majority PAC hammered at three quick arguments: that the tax cuts will primarily benefit the rich; that they will swell the national debt by $1.5 trillion; and that “to pay for the tax giveaway,” Republicans are planning “to cut Medicare for seniors.”

That last contention may be the most critical to the tax bill’s impact in November. Former President Bill Clinton won his epic budget showdown with a Republican-controlled Congress in 1995 and 1996 by linking the GOP’s tax cuts with its simultaneous proposals to cut Medicare and Medicaid. Democrats have to sell a more subtle argument today: that the huge revenue loss the tax cuts precipitate will eventually force congressional Republicans to retrench Medicare, Medicaid, and other safety-net programs. House Speaker Paul Ryan has made that linkage easier by urging precisely such cuts to the safety net, but the Senate has shown little interest in following suit this year. That means Democrats will need to work harder than Bill Clinton did to tie the tax cut with threats to Medicare and Medicaid.

“I think that message will be central to everything that Democrats do going forward on the tax bill,” predicted Democratic pollster Geoff Garin. In suburbs around the major metropolitan areas—ground zero in 2018—Democrats can also plausibly claim the bill will eventually raise taxes on many people by limiting mortgage and local tax deductions.