During the second half of 1967 the administration had become alarmed by criticism, both inside and outside the government, and by reports of declining public support for its Vietnam policies. According to public opinion polls, the percentage of Americans who believed that the U.S. had made a mistake by sending troops to Vietnam had risen from 25 percent in 1965 to 45 percent by December 1967. This trend was fueled not by a belief that the struggle was not worthwhile, but by mounting casualty figures, rising taxes, and the feeling that there was no end to the war in sight. A poll taken in November indicated that 55 percent wanted a tougher war policy, exemplified by the public belief that "it was an error for us to have gotten involved in Vietnam in the first place. But now that we're there, let's win – or get out." This prompted the administration to launch a so-called "Success Offensive", a concerted effort to alter the widespread public perception that the war had reached a stalemate and to convince the American people that the administration's policies were succeeding. Under the leadership of National Security Advisor Walt W. Rostow, the news media then was inundated by a wave of effusive optimism.