It has become one of the president's favorite lines. "My opponent has showed why he earned his ranking as the most liberal member of the United States Senate," President Bush said today at a rally in Colorado Springs, Colo.
But that remark is based on rankings given by the nonpartisan National Journal magazine, which says the president has his facts wrong.
"The Bush campaign has been misleading in the way they used our vote ratings," said Patrick B. Pexton, deputy editor of the National Journal. "John Kerry was the most liberal senator in 2003, a year when he missed many votes because he was on the campaign trail. But over his lifetime he is only among the most liberal senators."
The 11th most liberal, to be exact -- decidely not more liberal than Sen. Edward Kennedy, D-Mass., Pexton says, though the president also likes to make that claim.
The president used a different study to discuss Kerry's health care plan today.
"The facts are, eight out of 10 people who get health care under Sen. Kerry's plan will be placed on the government program," Bush said.
Bush campaign official Megan Houck said that figure is based on a study by the nonpartisan Lewin Group, a national health care and human services consulting firm.
What does the Lewin Group say?
"It's not eight out of 10 people," said John Sheils, vice president of the Lewin Group.
Of the 25 million people who would get insurance under the Kerry plan, Lewin Group says, about 6.5 out of 10 would be covered by Kerry's proprosal to expand the Medicaid program for poor people to others near the poverty line. Most of those would be individuals going from having no health insurance.
"It's not accurate," Sheils said of the Bush representation of his group's study.
On Monday in Sante Fe, N.M., Kerry unleashed a new line of attack against the president on why gas prices are so high. "One big reason is because of this president's gross mismanagement and miscalculation regarding the war in Iraq," Kerry said.
"There are a host of other reasons at play here," said Seth Kleinman, an energy markets specialist at PFC Energy, a Washington consulting firm. "There are issues in Russia, there's rampaging Chinese demand growth, there's a lack of tankers, a shortage of refinery capacity, so it's not exactly accurate to lay all of the blame on expensive gasoline on the war in Iraq."
Misleading statements are not just the purview of the presidential candidates, of course. In Iowa on Monday, Kerry running mate Sen. John Edwards -- noting the weekend death of spinal cord injury victim Christopher Reeve -- took the opportunity to note his ticket's support for full and unfettered medical research using embryonic stem cells, which Bush has severely restricted.
"America just lost a great champion for this cause, somebody who was a powerful voice for the need to do stem cell research and change the lives of people like him who have gone through a tragedy," said Edwards, D-N.C. "Well, if we do the work we can do in this country, the work that we will do when John Kerry is president, people like Christopher Reeve will get up out of that chair and walk again."
In the world of medical science, anything could happen, of course. But health care expert Sheils sums up the general consensus in the medical community when he says Edwards' promise is not "a realistic expectation."
"We have no guarantee that if we investigate stem cell research -- or any other kind of research -- that we're necessarily going to come up with an effective treatment, for any health condition," he said. "It's too much to say that we're going to see people walking again -- we hope it's true, but I think that's a little strong."
It's often said that facts are stubborn things. Perhaps not compared to ambitious politicians.
ABC News' Mary Marsh, Jared Wiener and Lisa Chinn contributed to this report.