Conservative David Frum on Sunday criticized some on the right for embracing "false and paranoid narratives" about President Barack Obama that he said were contributing to a toxic political climate.

"The thing I worry about is not rhetoric. It’s the construction of paranoid narratives," Frum, a former speechwriter for President George W. Bush who now runs his own blog, said on CNN's "Reliable Sources."

"When people say that Barack Obama is deliberately trying to destroy the economy of the United States in order to overthrow the constitution and lead us to a Marxist dictatorship – you can say that without a single harsh syllable or negative adjective, but it's a false and paranoid narrative, and that attacks the governance of the country," Frum said.

The former Bush aide insisted, however, that there were "comparable degrees of paranoia" among liberals when his boss was president, citing the belief that Bush deliberately lied the nation into war with Iraq. (The two central pretexts offered by Bush -- Saddam Hussein's weapons of mass destruction and ties to Al-Qaeda -- proved to be false.)

But, Frum conceded to host Howard Kurtz, "in the past couple of years, obviously, most [of the toxic talk] has come from the right, because there’s been a Democratic president."

His remarks came after the tragic shootings of twenty people in Tucson, Arizona by a gunman sparked off a national debate about the consequences of violent rhetoric and imagery in politics. Congress last week put off all legislative activities to mourn the victims.

Liberals have slammed conservative figures such as Sarah Palin, Glenn Beck and Rush Limbaugh for contributing to a climate of hatred they argue inspires such violence, something conservatives dismiss as political opportunism.

It is unclear what exactly motivated 22-year-old Jared Lee Loughner to go on a shooting rampage that killed a federal judge and critically injured Democratic congresswoman Gabrielle Giffords of Arizona.

The following video is from CNN's "Reliable Sources," uploaded by Media Matters.