Could "liberals" use NLP or perhaps involuntary hypnotism to convince people that their arguments have some slight merit? I don't know if "Don't Think of an Elephant: Know Your Values and Frame the Debate--The Essential Guide for Progressives" answers that question, but it was written by a linguist:

In the first of his three debates with George W. Bush, 2004 presidential candidate John Kerry argued against the war in Iraq not by directly condemning it but by citing the various ways in which airport and commercial shipping security had been jeopardized due to the war's sizable price tag. In so doing, he re-framed the war issue to his advantage while avoiding discussing it in the global terrorism terms favored by President Bush. One possible reason for this tactic could have been that Kerry familiarized himself with the influential linguist George Lakoff, who argues in Don't Think of an Elephant that much of the success the Republican Party can be attributed to a persistent ability to control the language of key issues and thus position themselves in favorable terms to voters. While Democrats may have valid arguments, Lakoff points out they are destined to lose when they and the news media accept such nomenclature as "pro-life," "tax relief," and "family values," since to argue against such inherently positive terminology necessarily casts the arguer in a negative light. Lakoff offers recommendations for how the progressive movement can regain semantic equity by repositioning their arguments, such as countering the conservative call for "Strong Defense" with a call for "A Stronger America" (curiously, one of the key slogans of the Kerry camp)...