Slogans are a crucial part of presidential campaigns. In just a few short words, they have to sum up a candidate's brand, while also inspiring voters to give them votes, their e-mail address and/or a few bucks in campaign contributions.

But some are better than others. Barack Obama's 2008 "Change We Can Believe In" is rightly remembered as a win. John Kerry's "Let America be America Again," not so much.

Given that we've now got an actual field of contenders for 2016 -- though it is by no means complete -- we thought we would review the slogans they have put forward. (We reserve the right to update this list going forward.)

Below, we rank them from the worst (No. 8) to the best (No. 1):

8. Hillary Clinton: "Everyday Americans need a champion. I want to be that champion."

So it's not her official slogan, but it's a sentence she used in her announcement video, it's prominently featured on her Web site, and when some Nevada high school students made a banner for her visit there this week, this is what they chose. In lieu of a slogan, it's what people are using.

While it basically sums up what all elections are about, it uses the phrase "everyday Americans," which we've established isn't a phrase actual "everyday Americans" actually use, and it's self-centered. Even though candidates are the entire reason for their campaigns, they're supposed to pretend they're not, by saying things like "we" and "us" instead of "I" and "me."

7. Ben Carson: "Heal. Inspire. Revive."

Single words can be an effective as campaign slogans, but in this case, three feels like overkill. It doesn't even necessarily feel political. It sounds like it could be for a spa or a multi-level marketing company that sells energy drinks.

6. Carly Fiorina: "New Possibilities. Real Leadership."

It's not necessarily a bad slogan, but it's a bit generic, isn't it? An American candidate could use it, but so could a British candidate or a Canadian one, or even a spookily omniscient and everpresent authoritarian leader of a futuristic Utopian society in a hit movie in theaters this summer based on a bestselling New York Times young-adult trilogy.

5. Ted Cruz: "Reigniting the Promise of America"

Cruz's slogan suffers from the overuse of similar slogans. Every election is about "reigniting the promise of America" or "taking America back" or "restoring our future," but if we're taking America back every four years, shouldn't it be taken back at some point? But it's certainly got the intended effect, even if it's not original.

4. Bernie Sanders: "A political revolution is coming"

It sounds a bit threatening and might owe royalties to Ron Paul, but at a time when trust in institutions has reached historic lows, a promise to revolutionize our politics is exactly what millions of voters are looking for. Also, it's very on-brand for the only candidate in the race who's ever been elected as a Socialist.

3. Marco Rubio: "A New American Century"

It gets at the whole "take back America" thing, but from a different angle. It feels fresher. And rather just promising four or eight years of peace and prosperity, he's promising 100. What a deal!

2. Rand Paul: "Defeat The Washington Machine. Unleash The American Dream."

Of all the official campaign slogans, it's the longest. But while it's wordy, it doesn't feel clunky because it's rhyming, almost sing-songy. There's action and energy to it. Defeat! Unleash! And you'll never confuse it for being anyone else's. It's very Rand.

(Side note: Who has put the American Dream on a leash? We should really find out.)

1. Mike Huckabee: "From Hope To Higher Ground"

Yes, it kind of sounds like a Christian rock album title, but that's actually pretty perfect for Huck, and there are many layers here. For one, it's optimistic. We're not destroying anything or reigniting anything violent like that. We're starting from hope, which is both a happy, positive place and reaching for more. It has a religious aspect to it, which conservative Christians will appreciate. Hope, Ark., is also Huckabee's (and Bill Clinton's) birthplace -- a more conveniently named hometown you will not find in these United States -- and "Hope" was a theme of Obama's first presidential campaign. So it suggests moving past Obama to something better. A unique slogan, packed with meaning.

It wins -- for now.