Following up on an item from a few weeks ago, Emily Heil reported yesterday on the most “taboo topic” at the Republican presidential candidate debates.

Viewers of the approximately 3 million Republican presidential debates so far have come to expect certain things. There’s the regular cast of characters, a moderator struggling to knock the candidates off their talking points, and loads of American flags.

But there’s one thing you’d be hard-pressed to find mentioned at a Republican debate.

George W. Bush? Who?

You’d think that the last Republican president — remember, that two-termer who’s only been out of the White House a scant three years — might come up frequently.

Not so. In fact, George W. Bush is the invisible man of the GOP race, the all-but-forgotten Ghost of Administrations Past. He’s its “He Who Should Not be Named,” in Harry Potter parlance.

There have now been 16 major debates for the GOP presidential field. The candidates have brought up President Obama by name 560 times. They’ve also invoked Ronald Reagan’s name 221 times. And what about the two-term Republican president whose policies these guys are eager to bring back? Poor George W. Bush has only seen his name come up “a pitiful 56 times.”

This, despite the fact that most Americans still hold Bush responsible for the sorry state of the American economy.

Let’s not forget the recent historical context here. Bill Clinton left the White House in January 2001, and in the 2004 race, Democratic candidates were tripping over each other to connect themselves to the nation’s 42nd president. I remember one September 2003 debate in which literally every Dem running for the party’s nomination said they’re the rightful heir to the Clinton legacy.

Al Sharpton, after a while, apparently couldn’t take it anymore. “I know that within the next hour we’ll say that Bill Clinton walked on water,” he joked.

We’re at a comparable point now with regards to Bush — three years after a two-term president left office, his party is looking to nominate a challenger to an incumbent. Dems in 2004 couldn’t stop referencing Bill Clinton, but Republicans in 2012 prefer to pretend Bush doesn’t exist.

This isn’t necessarily surprising. I don’t imagine many would-be GOP presidents were eager to bring up Hoover in the 1936 election, either.

But Bush deserves to be part of the discussion. From Dems’ perspective, there’s value in reminding voters that Bush is responsible for nearly all of the messes Obama is trying to clean up, and nearly all of the Republican candidates are eager to bring return to Bush-era policies — only this time, they’ll be even more right wing.

From journalists’ perspective, there’s no reason to play along with the GOP’s willingness to erase Bush from the larger discussion. Indeed, there are some pretty straightforward questions the Republican field should be forced to answer: Do you believe the Bush presidency was a success? How would your agenda differ from Bush’s if you’re elected?

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.