Democrats have for too long been passive in the face of the vast amounts of corporate money, most of it secret, that are being spent to evict them from office and dismantle their policies. By far the largest voice in many of this year’s political races, for example, has been that of the Koch brothers, who have spent tens of millions of dollars peddling phony stories about the impact of health care reform, all in order to put Republicans in control of the Senate after the November elections.

Now Democrats are starting to fight back, deciding they should at least try to counter the tycoons with some low-cost speech of their own. Democrats may never have the same resources at their disposal — no party should — but they can use their political pulpits to stand up for a few basic principles, including the importance of widespread health-insurance coverage, environmental protection and safety-net programs.

The leader of this effort has been Senator Harry Reid, the majority leader, who has delivered a series of blistering attacks against the Kochs and their ads on the Senate floor over the last few weeks. In addition, the Democratic Senatorial Campaign Committee has set up a website, www.kochaddiction.com, to remind voters of just what the Kochs stand for, and why they raised $407 million in the 2012 election. And individual candidates are making sure voters know who is paying for the ad blitz.

“The billionaire Koch brothers,” says one of the people quoted in an ad released Monday by Senator Mark Begich of Alaska, who has been the object of one of their blatantly false television barrages. “They come into our town, fire a refinery, just running it into the ground, leaving a mess.” Senator Kay Hagan of North Carolina reminds voters that the Kochs and their allies have pressed for high-end tax breaks that burden the middle class.