In tonight's Talking Points Memo, Bill O'Reilly said there is too much at stake in the 2016 presidential election for the campaign to be turned into a "smear-fest" by haters on the left or the right.

"At the height of the Iraq War, the vilification of President Bush the younger was off the chart," O'Reilly said. "The left in America accused him and Vice President Cheney of lying to get us into the war, of sacrificing American military people so Halliburton could make money and a variety of other vile allegations."

O'Reilly stated that he thought Bush was smeared even worse than President Clinton, who had to go through impeachment.

O'Reilly pointed out that President Obama is loathed by some Americans, and there is no question that the president's policies are controversial.

"He’s a big tax-and-spend guy, has increased the power of the federal government, has ordered a quasi-amnesty for some illegal aliens, has withdrawn completely from Iraq, leading to chaos, has imposed a health care system that many people despise," "The Factor" host said.

But on the personal front, though, Obama gets it too much, O'Reilly asserted. He pointed to two emails written in to the show.

"It’s time to impeach Obama and the Islamistration. This guy is clearly sabotaging our country" - Tom in Florida

"Obama is a Muslim, and many Muslims do not care about Christians. This president fights this crisis all over the world with politics and love for his Muslims." - Liz in New Mexico

"Talking Points laments the haters on both sides. Smearing anyone should be unacceptable," O'Reilly said, noting that in the upcoming presidential campaign, the Republican candidates surely will point out where they differ with President Obama and by proxy, Hillary Clinton.

"But any Republican candidate who says personal things about either the president or Mrs. Clinton will be making a tremendous mistake," O'Reilly said.

"The haters on both the left and the right make a lot of noise and get some attention, but most Americans don't like that kind of stuff. Once in a while, a takedown is necessary, but to make a living out of gutter-sniping? Ticket to defeat."

O'Reilly noted that America is in a bad place, weak overseas and with an economy that is still mainly rewarding the wealthy.

"President Obama has had six years to improve that situation, and in my opinion, he has failed to do so," O'Reilly said. "That's an objective analysis based upon facts, not a personal attack."

"Here's a final fact: I've had discussions with both George W. Bush and Barack Obama. They see the world very differently, but they both have absorbed tremendous punishment in order to serve their country."

"I respect that and hope that the upcoming presidential campaign will not be a 'smear-fest.' There is simply too much at stake for that to happen."

Watch the full Talking Points Memo above.