Our most recent rating of Republican presidential contenders features a top tier of three notably different candidates: A Midwestern governor (Scott Walker) who is known best by the activists who will help decide the nomination; a leading national figure (Chris Christie) who has irked conservatives; and a firebrand senator (Rand Paul) with devoted supporters who would shake up the party’s platform and, perhaps, identity.

Chart 1: Updated Crystal Ball Republican presidential rankings

First Tier Candidate Key Advantages Key Disadvantages Since Last Update Scott Walker

Governor, WI •Midwest GOP gov. in Obama state

•Heroic conservative credentials

•Shown political durability •Too bland? Next Pawlenty?

•Might not deliver home state

•Would highly motivate left/labor – Chris Christie Governor, NJ •Dynamic speaker

•Shown ability to pursue conservative agenda in Blue state

•Less is more — the future slogan of a svelte Chris Christie? •Superstorm Sandy fallout

•Not conservative enough for base?

•Loose cannon ↑ Rand Paul

Senator, KY •Tea Party favorite

•Strong support from libertarian GOP wing

•National ID and fundraising network •Too libertarian?

•Association with out-of-mainstream father

•Too dovish/eclectic for GOP tastes? ↑ Second Tier Marco Rubio

Senator, FL •Hispanic

•Dynamic speaker and politician

•From most electorally valuable swing state •Future tough votes in Senate; has and will have federal record

•Vetting issues regarding family

•Could he really deliver more Hispanic votes? ↓ Ted Cruz

Senator, TX •Tea Party favorite

•Texas fundraising

•Conservative voting record •Too extreme?

•Disliked on both sides of the Senate aisle

•Eligibility questions ↑ Rick Santorum

Fmr. Senator, PA •Strong support from social conservatives

•2nd place finisher in ’12 – next in line?

•Bring around primary track •Too conservative for general election?

•Lost last Senate race by 17%

•Foot-in-mouth troubles ↑ Third Tier Bobby Jindal

Governor, LA •Brings diversity

•Southerner in Southern party

•Extensive state/fed. experience •Controversial governorship

•Not nationally vetted

•Not a dynamic speaker ↓ Paul Ryan

Representative, WI •2012 VP candidate – next in line?

•General election experience

•Strong conservative record •May not want to run

•Couldn’t help Romney carry WI

•Not a dynamic campaigner ↓ Rick Perry

Governor, TX •Strong conservative credentials

•Texas fundraising

•Extensive executive experience •Ran very poor 2012 race

•”Oops,” we forgot the rest – Wild Card? John Kasich

Governor, OH •Swing state

•Long conservative record

•Ohio’s unemployment below national average •Supports Medicaid expansion

•Legislative resistance to budget

•Abrasive personality –

Christie and Paul — both of whom have moved up our list — were engaged in a very public spat recently over the size of government and the national security state. Christie adopted a more traditional Republican view, warning against the dangers of libertarian positions on national defense. In so doing, he squarely placed himself within what has been, at least recently, the Republican mainstream: The defense policies of President George W. Bush and recent GOP presidential nominees John McCain and Mitt Romney were certainly more hawkish than dovish.

Paul, meanwhile, has made a national name for himself by questioning national security policies, and his biggest moment this year was his filibuster against the use of drones.

Needless to say, a Republican presidential nomination battle headlined by Paul and Christie would present Republicans with a real “time for choosing,” to borrow the title of the famous speech Ronald Reagan gave in support of Barry Goldwater near the close of the 1964 presidential campaign, with Christie offering a traditional Republican platform and Paul pulling the party in a more libertarian direction, both in foreign and domestic policy.

Meanwhile, Scott Walker continues to hold the top spot on our list because we believe that if he decided to run, he could potentially appeal to both the party’s defense hawks and its fiscal conservatives. In the event of a Paul-Christie duel (or a battle among others) for the soul of the Republican Party, Walker could present himself as a consensus choice whose nomination would avert a GOP identity crisis. Yes, we realize that Walker might end up being a disappointing national candidate — he very well might not have the swagger, fundraising chops, rhetorical ability and national base of support to make much of a bid — but in our view he continues to lead a wide-open field.

We’ve moved Sen. Marco Rubio (R-FL) down the list. His prominent role in the Senate’s immigration debate has done him some damage in early polling: There’s evidence that he has recently slipped in Iowa and New Hampshire, and that his national star has faded at least slightly amongst Republicans. This all could be some early, meaningless noise, but if one has to rank the GOP presidential contenders, he just doesn’t belong above Walker, Christie or Paul at this point. Bob Vander Plaats, an evangelical leader in Iowa, said that some Iowans he’s talked to believe 2020 might be a better opportunity for Rubio than 2016. Easy now — there’s many months to go before even 2016 comes into focus.

Nipping on Rubio’s heels is Sen. Ted Cruz (R-TX), who is steadily moving up our chart after we added his name in May. Cruz is championing a government shutdown over defunding Obamacare. Republican leaders — smartly, we believe — think that such a maneuver would end up doing them political damage. Assuming a shutdown is averted, Cruz can essentially have his cake and eat it too — he can maintain his hardline position on a shutdown without having to deal with any potential blowback if the shutdown had actually happened. Cruz and Paul are thought of as ideological kindred spirits, and they are on some issues (like defunding Obamacare). But Cruz isn’t the defense libertarian that Paul is, it seems (on defense, Cruz says he’s between John McCain and Paul).

The people who might be most drawn to a Cruz candidacy are the kinds of voters who supported Rick Santorum in the 2012 primary. That might actually be a problem for Santorum, who could seem like yesterday’s news in a presidential field that is probably going to be more star-studded than 2012. But let’s not count out Santorum, who as the runner-up last time is historically in a decent position in the Republican presidential pecking order.

Rounding out our list is Gov. Bobby Jindal (R-LA), whose national star could be fading; Rep. Paul Ryan (R-WI), who remains popular amongst Republicans but who seems likelier to pass on a run; and Gov. Rick Perry (R-TX), who will have plenty of time to barnstorm the early primary states after he leaves office in 2015 but who may have irreversibly damaged himself in the 2012 primaries.

The Democrats: Could anyone upset Clinton?

Wasn’t Hillary Clinton supposed to disappear for awhile after leaving her Cabinet post? Yet not a day goes by without Hillary Clinton giving a paid or policy speech, getting an award, lunching with the president, or having another television mini-series about her announced.

Whatever happened to the concept of peaking too early, and didn’t she peak too soon in the 2008?

It is worth considering, especially as we consider a seemingly impossible thought experiment: Could Clinton run, but lose the primary?

That appears very unlikely, but remember that a Clinton nomination appeared inevitable in the early going of the 2008 race (although Clinton did not have the towering poll numbers among Democrats that she does now).

To us, there’s one remote but clear possibility who could credibly challenge Clinton in a primary: Massachusetts Sen. Elizabeth Warren.

We continue to hear faint whispers of opposition to Clinton among some Democrats, particularly among the party’s young, Obama-supporting activists. Warren, who has a notably liberal background and who could have the same glass-ceiling shattering effect as Clinton if nominated, is the obvious person to challenge Clinton, if she wanted to. The grassroots on the left would find her an attractive alternative if Clinton is once again viewed as too establishment, or if Bill becomes controversial again — always a possibility. So we’re moving Warren up a notch on our Democratic presidential list, shown as Chart 2.

Chart 2: Updated Crystal Ball Democratic presidential rankings

First Tier Candidate Key Advantages Key Disadvantages Since Last Update Hillary Clinton

Fmr. Sec. of State •High national popularity

•Woman: chance to make history

•Likely to unify party forces if she runs (unlike ’08) •Age (69 by Election Day ’16)

•Did not run strong ’08 campaign

•Keeping Bill in check and on the porch – Second Tier Joe Biden

Vice President •Vast experience

•Next in line? Will Obama back him?

•VP bully pulpit •Age (already 70)

•Gaffe machine

•Poor pres campaign history – Third Tier Elizabeth Warren Senator, MA •Adored by Dem activists

•Woman

•National ID and fundraising network •Little crossover appeal

•’12 campaign baggage

•Another Bay Stater? ↑ Andrew Cuomo

Governor, NY •Very popular at home

•Impressive policy record already

•State/Fed. experience •Too conventional?

•Some liberals unhappy

•Another Northeasterner? ↓ Fourth Tier Mark Warner

Senator, VA •Strong executive record

•Key swing state

•Crossover appeal/ bipartisanship theme

•Well-financed •Too moderate?

•No national constituency

•Not a dynamic speaker – Kirsten Gillibrand

Senator, NY •Woman

•Strong liberal record

•NY fundraising base •Bland persona

•Nationally unknown

•Past NRA support? – Martin O’Malley

Governor, MD •Willing and very available

•Strong liberal record and policy achievements •Maryland=small base

•Little crossover appeal

•Nationally unknown – Brian Schweitzer

Fmr. Governor, MT •Westerner

•Unique populist personality

•Very popular Dem in

Red state •Westerner

•Unique personality

•Too unpredictable? – Wild Card? John Hickenlooper

Governor, CO •Swing state

•Crossover appeal

•Westerner

•Gun control backer •Nationally unknown

•Not a dynamic pol

•Interest in running? –

Many of the possible candidates on this list probably wouldn’t run if and when Clinton announces her candidacy; they could be scared off by her imposing polling advantages and the power of the Clinton brand, which has only strengthened in the Obama years.

What would an anti-Clinton insurgency by Warren or another Democrat look like? Other than Clinton fatigue — generated as much by Bill as Hillary — it would depend on the Democratic primary electorate having a long memory of Clinton’s support of the Iraq War. While it’s hard to imagine any Democrat running an explicitly anti-Obama campaign, it is possible that a Clinton primary challenger would run to the left of both her and Obama, perhaps by supporting the “public option” that was left out of the Affordable Care Act or advocating a major curtailing of the NSA, CIA and the national security state.

Anyway, it’s August 2013 — which is a great time to speculate on such things. The truth is, the Democratic field is static, and will mainly remain so if Clinton runs. The atoms come apart and the Democratic universe disintegrates if Hillary says no dice, at which point anything goes.