Congress looks for ways to trim the federal budget, they might want to be careful of how closely they listen to their constituents. That's because several polls have shown that Americans are typically terrible estimators of how much money the U.S. spends on particular areas of the budget -- suggesting that public opinion about potential cuts is often influenced by gross misconceptions. Reining in government spending and reducing the deficit were central to the Republican Party's platform in last year's midterm elections, when the GOP reclaimed control of the House. Amid a sluggish economy and a ballooning deficit, polls have consistently found that overwhelming majorities of Americans agree with the idea of paring down federal spending; a CNN poll in January found 71% of Americans supported the idea trimming the federal budget. Yet when it comes time to get specific, the cuts that Americans are by and large in agreement on don't add up to much. While they want Congress to drastically reduce spending overall, they overwhelmingly oppose doing so by scaling back some of the budget's biggest pieces. Essentially, Americans want to have their budget cake and eat it too. For instance, foreign aid is one of the only areas that most Americans are willing to squeeze for savings. In a recentGallup poll, foreign aid was the only piece of the budget where a clear majority of Americans supported budget cuts. Fifty-nine percent of respondents said they favored cuts to foreign aid, versus 37% who opposed such cuts. At the same time, over half of respondents opposed trimming any of the eight other budget items presented in the survey -- including Social Security, education, and defense. A January CNN poll found the same result, with 81% of Americans supporting cuts to foreign aid, while opposing, by around the same margin, cuts to Social Security and Medicare (which alone comprise roughly one third of the overall budget). So how much money do Americans think could be slashed from international aid? In a World Public Opinion poll conducted last November, respondents guessed, on average, that foreign aid spending represented 27% of the federal budget. To trim spending, the same respondents suggested that, on average, foreign should make up a slimmer 13% of the total budget, surely delivering massive savings. The problem? Foreign aid is actually a minuscule 1% of the total budget. Even eliminating it altogether would do little to balance the budget or reduce the deficit. This same sticking point -- Americans' misconceptions of actual spending levels -- seems to work the other way around when it comes to the military. When it comes to defense spending, Americans generally oppose cuts and wildly underestimating how much is already being spent. In the previously-cited Gallup poll, nearly six in ten respondents opposed cutting defense spending. Meanwhile, a Rasmussen poll released last week found that 37% of Americans thought defense outlays were fine at their current levels, while 32% thought defense spending was too high, and 27% thought it was too low. Yet the Rasmussen survey also asked this question: To ensure its safety, should the United States always spend at least three times as much on defense as any other nation?Only 25% of respondents agreed with that statement, compared to 40% who disagreed. In reality, though, the U.S. spends more than that -- much, much more. Total defense spending for 2011 is estimated at $719 billion, seven times higher than the approximately $100 billion in annual military expenditures by the next highest spender, China. In effect, that meant that the poll's participants contradicted themselves in the span of a few questions, both opposing cuts to defense spending, while also -- unknowingly -- saying the U.S. already spends too much on its military. This all suggests that though Americans are eager to have the government roll back spending, they don't have a plan for doing it -- and when they do offer cuts, they overestimate the impact that those cuts will have. If Congress really does attempt to pare down spending, they'll be walking a politically perilous tightrope, forced to balance calls for a slimmer budget with opposition to all but the teeniest of cuts.