It's been an amazing week 0n Capitol Hill following the stunning primary defeat of House Majority Leader Eric Cantor on Tuesday. Over the last 24 hours Paul Kane, WaPo's senior congressional reporter, and I exchanged a series of emails trying to figure out what it all means.  Our email back and forth is below, edited only for grammar and flow.

FIX: Ok, PK. Eric Cantor loses on Tuesday night. Conservatives insist this is their time to gain a real voice in their party's leadership. Less than 48 hours later, Kevin McCarthy — the current Majority Whip and not exactly a "movement" conservative — has the race to replace Cantor locked up.

What gives?

US House Majority Leader Eric Cantor speaks during a press conference announcing his resignation as Majority Leader at the US Capitol in Washington, DC, June 11, 2014. SAUL LOEB/AFP/Getty Images

PK:  It’s a remarkable turn of events, I’ll say. Let’s just set aside the entire HOLY COW aspect to Cantor’s defeat (or a few other unprintable words), and let’s focus on the conservatives.

Our friend/colleague/mentor Dan Balz gave labels that might help define what we’re talking about: the “business wing” versus the “populist wing” of the party. Those populists inside the House Republican Conference – up to about 50 of them who are very anti-Wall Street/anti-big industry/anti-big military – are frequently the loudest voices in the media, making the most threats.

They essentially took the reins of power from [House Speaker John] Boehner and Cantor in October and engineered the government shutdown. Now they have a shot to put up a candidate for the No. 2 spot in leadership and they have … no one. [Idaho Rep. Raul Labrador is considering the contest but is regarded as a major long shot.]

“They failed to show up,” Devin Nunes told a few reporters Thursday.

Jeb Hensarling considered the race, and he would have drawn the base of his support from the populist wing, as his chairmanship of Financial Services has been marked by its anti-corporate tone.

Nunes voices on the record what many say privately: these populist wing members are not the hardest working in the conference, far from it, that they enjoy throwing brickbats on the sidelines and making talk radio appearances, but they don’t put in the actual mileage that it takes to become a top leader.

FIX:   If that's the reality, it may well make the House totally ungovernable though, right?

The populist/tea party wing doesn't have enough votes/organization/wherewithal to put one of their own in leadership but they have plenty of votes to make it impossible for the business conservatives who are in leadership to, well, lead, right?

That feels like the story of the last three plus years for John Boehner.  The populist wing didn't have enough votes to beat him but man oh man have they made his legislative life a living hell.  How will that possibly be different with McCarthy?

And, while we're at it, Rich Galen, former Newt guy, suggested to me on Twitter Thursday that the populist wing of the party not putting up a big fight for majority leader might be evidence that they are saving themselves for the real fight: The Speakership battle in December. Buy it?

PK: Your “ungovernable” point was definitely the case from 2011 through 2013, with crisis after crisis ending with the populist wing undercutting Boehner in pursuit of partisan purity, leaving him no leverage and ending up passing critical legislation with a heavy dose of Democratic votes. But many Republicans believe the government shutdown was a touch-the-stove moment, or even a put-your-head-in-the-oven moment, and for the most part there’s been a solid bloc of 170 or more Republicans who’ve regularly supported bipartisan bills [since then]. Heck, earlier this week, leadership got 215 votes from their side of the aisle for the transportation funding bill (aka THUD, best acronym of any annual spending bill!).

This was the very bill that last year McCarthy told leaders they lacked the votes for and had to pull it from the floor, setting in motion the chain of events that really led to the shutdown.

As for the speaker’s race, well, I just think it’s hard to believe that if Hensarling had the votes to be Leader, he would just take a pass on that race.

Knocking out McCarthy now would make Hensarling the unquestioned speaker-in-waiting. Giving McCarthy – considered less of a substantive guy than other leaders – six months, or 2 1Ž2 years, to grow into the No. 2 job seems to be a very risky bet.

Let’s take Galen’s own mentor, Newt, and how a previous chairman, Bob Livingston, used his outside clout to vault into the top slot. In 1998 Newt was taken out by Livingston after the poor midterms, but the reason Livingston was so poised to deliver the TKO was because he had spent the previous six months running for Majority Leader – people forget this, but Livingston had basically locked down the votes to oust Dick Armey and that was his focus.

So Livingston was set to become Leader, but after the terrible midterms, he got urged to jump into the speaker’s race and that pushed Newt quickly out the door. Livingston was poised to do that because he had been preparing for months and months, asking for support and raising money for people.

There’s little indication that Hensarling is doing that now.

FIX:  So McCarthy wins, has a chance to grow into the job and then what…

I continue to wonder whether/how Boehner can get the votes to be Speaker. I assume McCarthy, as majority leader, works to help Boehner get re-elected Speaker. But, if Boehner gets forced to a second ballot, does McCarthy turn on him and go for Speaker himself?  And, let me end where we started: how the heck can the populist wing possibly feel as though they accomplished anything with Boehner and McCarthy, whose politics seem pretty darn close to Cantor's, in the top 2 slots? Even if the populist tea party folks win the whip race is that really enough?

PK:  This is the big question inside the House GOP, whether or not there are 20-25 or more Republicans who would refuse to vote for Boehner on the January ballot and send it into a chaotic second ballot that could result in another Republican emerging. Until this week it was really unclear -- and now it's even more unclear.

Some of those folks who were Boehner antagonists during the January 2013 vote actually wanted to turn over the speaker's gavel to Cantor, but he's now gone. I'm not sure that those folks are comfortable immediately elevating McCarthy to the top spot, so they might be convinced to support Boehner.

In that 2013 vote, the math was this: 12 Republicans voted for someone else, declined to vote or just voted "present"; four more took a pass on the first round of voting in the alphabetical roll call, only to support Boehner once it was clear he had the bare minimum to have a majority. At least two of them are retiring at the end of the year, giving leadership allies time to court their successors, and there could be more newcomers if Republicans does as well as they expect in the fall.

A lot of this tension may get resolved in the No. 3 race, the battle to succeed McCarthy if he does win the Leader race. Populist conservatives really want one of their own to at least have the whip slot, particularly southerners. Of the three contestants there, at least one (Marlin Stutzman of Indiana) is a true-blue conservative. Steve Scalise (R-La.) chairs the influential Republican Study Committee, but the most conservative lawmakers saw him as a favorite of Boehner-Cantor, a fun-loving southerner who deep down isn't as conservative as the most strident of his caucus.