In New York Times Co. v. Sullivan, the U.S. Supreme Court ruled that journalists may not be sued successfully by public officials for libel unless their news coverage was false, damaged a reputation and was published with “actual malice.” That meant establishing that the defamation was published “with knowledge that it was false or with reckless disregard of whether it was false or not.” The Court concluded that such protection was necessary to preserve open debate and discussion about government policy and conduct. Without that protection, the First Amendment guarantee of a free press was largely subject to widely disparate state laws, none of which provided a similar shield against lawsuits.
"Elect me and we will repeal Obamacare. Elect me and I will seal the Border..." Etc. The founders did not intend for free speech to provide cover for defrauding voters.