Condoleeza Rice, testifying before the 9/11 Commission, explained that President Bush's phrase "I'm tired of swatting flies" referred to the President's demand that the United States formulate a strategic policy to confront terrorism, to replace the decade's-old U.S. approach of responding piece-meal, or not at all to terrorist attacks. As she spoke, Commissioner Bob Kerrey shouted her down, demanding "what flies did [Bush] swat?" Kerrey then refused to allow the witness to respond, evidently not wanting an answer so much as a sound-byte for the evening news.
Perhaps this is beyond the capacity of the partisan thinking of professional politicians like Bob Kerrey, but George W. Bush, as an American citizen, identifies himself with The United States of America. So that the past two-plus decades of U.S. response to terrorism - sagaciously described as "swatting flies" - is what we Americans had been doing heretofore about the problem, and what Bush was tired of doing. As you might say, "I'm tired of not responding to these terrorists attacking our troops in Iraq with bombs and RPG's," even though you have not personally been in a position to do anything about it. As an American you identify with our nation's efforts. President Bush, at last in a position to shape policy, acted to change what we Americans would do henceforth.
For those who think of themselves first by Party affiliation, and only second, third or fourth as Americans (ranked after, according to individual, after Citizen of the World, Race, or Ethnic Background identifiers), the significance of the phrase "I'm tired of swatting flies" eludes understanding entirely.