Already, they have committed at least $17 million to television commercials in more than a dozen states from Florida to Hawaii, in most cases dwarfing what their Democratic opponents have spent. Their plans call for an effort that will exceed $100 million by Election Day, strategists for these groups said, far surpassing their efforts in 2010, a high-water mark for outside money in politics. In the weeks ahead, they will pour more resources into states like Nebraska and Missouri, which have already seen some of the heaviest spending, in addition to intensifying their campaigns in New Mexico, West Virginia and Wisconsin. Their immediate objective: use hard-hitting television ads to tether Democratic candidates to the budget deficit, lackluster economic growth and the perception that government has become too intrusive and unmanageable. Except for the candidate, and the phone number that flashes on screen at the end, the ads follow a strikingly similar script. Senator Fill-in-the-Blank supports business-smothering regulations and will raise your taxes. He also added trillions to the deficit by voting for “Obamacare” and will cut your Medicare. In Missouri, Senator Claire McCaskill, a Democrat, has been buffeted with more than $2.2 million in television ads from Crossroads GPS, the U.S. Chamber of Commerce and a group called the 60 Plus Association, which bills itself as a right-leaning AARP and uses Pat Boone as its pitch man. “Call Senator McCaskill,” Mr. Boone says in one ad. “Tell her unaccountable bureaucrats should never have the power to deny you the care you deserve.” Ms. McCaskill and her allies have countered with ads of their own but are being outspent by more than 3 to 1, data from Kantar Media show. In Nebraska, Bob Kerrey has been mocked as a liberal Manhattan interloper in a trio of TV commercials from Americans for Prosperity. In one, set to music that vaguely recalls Bernard Herrmann’s score from “Psycho,” a narrator warns, “Bob Kerry is moving back to Nebraska, and he wants to bring his liberal agenda back to our Nebraska home.” Stern-faced citizens object. “Not in my house,” says one man. “Not here,” says another. Mr. Kerrey, a former Nebraska governor and senator who left office a dozen years ago to run the New School in Manhattan, has responded with nearly half a million dollars in commercials of his own. That is a considerable expense for his fledgling campaign, and almost as much as the amount of cash he had on hand at the end of March. The conservative groups’ strategy makes clear that they — traditional Republican allies like the Chamber of Commerce along with newer players like the Karl Rove-backed Crossroads GPS and Americans for Prosperity, a Koch brothers-affiliated venture, among others — intend to be even more aggressive this year than they were in 2010, when they greatly expanded the role of outside money in Congressional elections. By forcing their opponents to respond with expensive ad campaigns of their own, these conservative groups are achieving at least part of their goal. But their strategy is not without its risks, namely that they are dumping money into advertising long before voters are really paying attention. The focus on the Senate reflects conservative hopes for a sweep of the White House and both branches of Congress, and frustration with the Senate’s role in blocking legislation passed by the Republican-controlled House, especially on the budget and fiscal issues that have come to dominate the debate in Washington. “You could argue that what happens in the Senate and the House matters more on a day-to-day basis, on key legislative matters, than an administration does,” said Tim Phillips, president of Americans for Prosperity. The Chamber of Commerce, which, according to the Center for Responsive Politics, spent more than $30 million on Congressional races in 2010, said it will commit “measurably more” this year to House and Senate campaigns in what officials called the most significant political effort in its 100-year history. “We’re going to shape the environment now instead of waiting for the environment that comes to us later,” said Rob Engstrom, national political director for the Chamber of Commerce. For over a year, the group has enlisted strategists to comb through candidates’ voting records and public statements, looking for material useful in an ad. “We’re prepared to quickly engage if developments warrant,” he added. Crossroads plans to spend about $60 million on Senate races alone and an additional $30 million on House races. That would more than double what it and its sister organization, American Crossroads, spent in 2010. These sums will come atop the nearly $18 million in air time that the National Republican Senatorial Committee has reserved for the fall. Americans for Prosperity, which has been an important supporter of the Tea Party movement, and others promoting various aspects of the conservative agenda, like Club for Growth, a group that promotes fiscally conservative and free-market principles, have each vowed to spend millions more. Democrats acknowledge that they are outgunned, but expect the Republicans’ financing advantage to dissipate as the general election nears. Money being spent on ads now, Democratic strategists argue, is being wasted on voters who are not paying close attention to their local races. And it will leave less money for Republicans and their allied groups come the fall, they contend. “Even Karl Rove’s money becomes finite at some point,” said Matt Canter, communications director for the Democratic Senatorial Campaign Committee, who added that Democratic incumbents had plenty of cash on hand that would go further because candidates, unlike outside groups, get the lowest possible advertising rates. “We will not be outspent in practice as much as it might appear.” In addition to lacking the large donors who have provided much of the money for outside conservative groups, Democrats find themselves at a further disadvantage because President Obama’s campaign and the Democratic National Committee do not plan to finance the Congressional campaign committees this year. Democrats are trying to turn their underdog status into a political benefit by using it to raise money and portray their Republican opponents as beholden to their big contributors. Indeed, Ms. McCaskill features the attack ads being run against her in an ad of her own that rails against the “special interests” behind the commercials. “What they’re doing to Claire McCaskill is nothing compared to what their special interest agenda will do to you,” the narrator says, going down a list that includes tax breaks for the wealthy, “ending Medicare as we know it,” and trade policies that benefit China over the United States. “Claire says, ‘Make it in Missouri,’ ” the announcer adds, pronouncing it the way many locals do: Muh-zhur-UH.