David Hill, a Republican strategist who writes a weekly column published in The Hill, claimed in his April 1 column, “Military men like John McCain learn their craft through the study of history. ... But political candidates like McCain are seldom so well-prepared when it comes to fighting campaign wars.” Hill added that “the failures of [former Massachusetts Gov.] Mitt Romney's assaults on McCain confirmed his [McCain's] view that negative ads don't win campaigns.” In fact, as Media Matters for America has documented, McCain engaged in negative campaigning against Romney during the 2008 Republican presidential primary contest. McCain also engaged in negative campaigning during his failed 2000 bid for the presidency.

In a December 28, 2007, press release, McCain's campaign announced the release of its TV ad "Consider," which includes a quote from a Concord Monitor editorial that read, “If a candidate is a phony ... we'll know it. Mitt Romney is such a candidate.” Time magazine senior political analyst Mark Halperin reported on his Time.com blog, The Page, that the ad was the “first negative ad by any candidate besides Romney.” In a December 28, 2007, post on ABC News' blog Political Radar, Matt Stuart reported that Romney responded to the ad, saying: “It's an attack ad. It attacks me personally. It's nasty. It's mean spirited. Frankly, it tells you more about Sen. McCain than it does about me that he would run an ad like that.”

In a January 29 article about that day's Florida Republican primary, The Washington Post's Michael D. Shear and Perry Bacon Jr. reported that the “angry tone between [Romney and McCain] extended to the airwaves, as McCain launched a new negative radio ad.” The Post noted that “McCain's new radio ad mocks Romney's economic record as governor and questions his electability, with an announcer saying, 'The bottom line: Mitt Romney loses to Hillary Clinton. Republicans lose. We can't afford Mitt Romney.' ”

McCain also criticized Romney in numerous Web ads: "Experience," released January 1; "Foreign Policy Alert," released January 2; "Leadership," released January 4; "Mittsurfing," released January 24; and "A Tale of Two Mitts," released January 28. In two of the ads, McCain attacked Romney for allegedly “chang[ing] positions” on issues ranging from “the Bush tax cuts,” abortion rights, Second Amendment rights, and even "[o]n being a Republican."

Additionally, as Media Matters noted, McCain released a negative ad criticizing Sen. Hillary Clinton's support for a $1 million earmark for a museum at the Bethel Woods Center for the Arts, located “at the site of the original 1969 Woodstock Festival” in New York, although McCain himself had skipped the vote on removing the earmark.

McCain also engaged in negative campaigning during the 2000 Republican presidential primary. During that race, McCain admitted to using negative advertisements against then-Gov. George W. Bush, and his campaign admitted to making phone calls that were perceived as negative against Bush.

From Hill's April 1 column:

Conventional wisdom holds that Republican Sen. John McCain (Ariz.) would rather run against Sen. Hillary Rodham Clinton (D-N.Y.) than Sen. Barack Obama (D-Ill.). With negative opinions swirling around her and growing, it would seem the logical choice to prefer a race against Mrs. Clinton. But the opposite is probably true. John McCain knows that a campaign against Bill and Hillary Clinton would be a bloody battle that he'd rather avoid. Campaigning against Barack Obama would be a more civil affair.

Military men like John McCain learn their craft through the study of history. Great battles are examined for insights on strategy and tactics. When John McCain came out of the U.S. Naval Academy, he probably knew what sort of war he would wage if ever given command responsibility.

But political candidates like McCain are seldom so well-prepared when it comes to fighting campaign wars. Sure, a few first-time candidates may have hung around a campaign or read a political memoir, but most learn the craft of waging political war through personal experience.

In the case of John McCain, there is little to suggest he's well-prepared to win a highly negative battle with warriors like the Clintons.

[...]

[A]s he entered the 2000 presidential race, McCain became the staunchest critic of negative advertising and received many plaudits across the nation for his clean-campaign pledge, particularly from the editorial press and big Republican donors. The latter generally detest bloody primaries.

Such positive feedback undoubtedly reinforced McCain's sense that people don't like negative campaigns.

The sordid mess in South Carolina's 2000 primary against Bush sealed that impression. And the failures of Mitt Romney's assaults on McCain confirmed his view that negative ads don't win campaigns.

So John McCain wants Barack Obama for an opponent. Their styles, emphasizing contrasts and comparisons rather than attacks, are better suited for each other.