It’s become a tradition in presidential politics that wanna-be candidates write books before a presidential run. It is a way of announcing without announcing your ambitions and is supposed to show gravitas. For a candidate like Mitt Romney it was supposed to clarify where he stood on issues and demonstrate some foreign policy know-how.

It is no surprise that Hillary Clinton and Wisconsin Gov. Scott Walker are both writing books, since the former is almost certainly going to run and the latter may do so as well. They have radically different assignments, however. Clinton’s is essentially defensive — making sure the bad stuff in the Obama administration (most of it foreign policy) isn’t seen as her fault. (She would be wise to avoid the phrase “What difference does it make?”) Walker’s is about reminding voters what he’s done and lifting his profile. Lots of candidates could benefit from book writing. Some, such as Sen. Marco Rubio (R-Fla.), already have done so.

Here are some suggestions:

Gov. Chris Christie’s “You Try Running New Jersey!”: After what will certainly be a cakewalk reelection race, Christie, if he wants to run for president, would do well to remind Republicans just how conservative his record is on taxes, spending and entitlement. He can’t be too defensive about his embrace (literally) of the president before the 2012 election, but he can use some pointed humor (“Romney had bigger problems than my graciousness“). Most of all, he’ll have to present a formula for connecting with badly needed urban, suburban and ethnically diverse voters while assuring Republicans he’s a pretty conservative guy.

Sen. Rand Paul’s “Defending America”: His biggest hurdle if he wants to run for president is convincing voters he is sober, serious and prepared to be commander in chief. That means spelling out in some detail what he knows and what his foreign policy vision is. He too often sounds like he is more concerned with defending us against the U.S. government than foreign enemies. If he can’t with the help of a “co-writer” (all these guys have someone who does the real work) convince readers he’s got a mature worldview, he won’t be able to do it in a campaign.

Rep. Paul Ryan’s “My Time”: He could use, if not a tell-all, then an explanation of the sort of race he wanted to run in 2012 and the policy vision he’s put into GOP House budgets. There should be a way for him to break free of his image as a “numbers guy,” share what he saw in America on the trail and reveal how his personal story in small-town America informs his views. He’s among the most genuine Republican politicians on the national stage, and he needs a platform to let that come through.

Virginia Gov. Bob McDonnell’s “Winning for (GOP) Dummies”: He’s got an impressive record that most voters outside of Virginia barely know about and the tag of being boring. He could use the opportunity to explain in humorous fashion to fellow conservatives how not to scare voters (especially women), how to win in a swing state and then debunk the reputation of a right-winger who doesn’t want government to work.

Former Florida governor Jeb Bush’s “Remember Me?”: Bush’s biggest problem is that few remember he was governor, let alone what he did. He’s known now for being an immigration-reform proponent, but he had a solid record on education, the environment, taxes and hurricane disaster cleanup. If he can explain to a new generation of readers that he’s not just the former president’s brother, he’d get more buzz.

Vice President Biden’s “Not My Fault”: By the time 2016 rolls around, Obamacare will likely be in shambles, and one or more foreign policy missteps will have had serious, negative consequences. He’d do well to explain how he had no power, no responsibility and was invariably on the other side of a whole lot of issues. If possible, he should tie Hillary Clinton to as many goofs as possible.