Sen. Mitch McConnell ( R-KY) greets supporters during the 133rd Annual Fancy Farm Picnic in Fancy Farm, Ky., Saturday, Aug. 3, 2013. McConnell is seeking reelection in a race expected to top campaign spending records. (AP Photo/Stephen Lance Dennee) (Stephen Lance Dennee/AP)

In 2012, President Obama became the first candidate to raise and spend more than $1 billion on a single race. In 2014, Mitch McConnell’s reelection bid in Kentucky may result in the first Senate contest to crest the $100 million mark.

“Spending has spiraled since campaign finance ‘reform’ passed, and it was inevitable that the $100 million mark would be breached someday,” said Ben Ginsberg, a leading Republican election and campaign finance lawyer.

Races in recent years have come close to breaching the $100 million level. The Senate race in Massachusetts between Scott Brown (R) and Elizabeth Warren (D) carried an $82 million price tag, making it the most expensive contest in Senate history. (The massive spending in that race is all the more remarkable when you consider that neither Brown nor Warren had significant personal money to spend on it.) For more than a decade before the Massachusetts race, the 2000 Senate fight in New York between Hillary Clinton (D) and Rick Lazio (R) held the record for spending at $70 million.

There’s good reason to believe that the race between McConnell (R) and Kentucky Secretary of State Alison Lundergan Grimes (D) could blow past those past records.

Let’s walk through the numbers.

In 2008, McConnell spent just north of $21 million — including a $2 million personal loan — to beat Democrat Bruce Lunsford, who pumped nearly $8.6 million of his own money into the losing effort.

McConnell is ahead of his 2008 fundraising pace, having collected nearly $14 million for the 2014 election, and is sitting on a campaign war chest of $9.6 million.

And, unlike in 2008, McConnell will face a primary fight, from wealthy businessman Matt Bevin. While it’s unclear how much of his own money Bevin will spend, those who have done some digging into his wealth — he has yet to file financial disclosure statements for his Senate bid — believe that he has the capacity to put several million dollars into the race.

McConnell, clearly concerned about the Bevin challenge, has already run two TV ads ahead of the primary, and you can bet there are lots more where those came from. It’s hard to see how McConnell escapes the primary for anything less than $5 million.

In fact, McConnell allies and other Republican observers well versed in fundraising estimate that the senator will end up raising and spending somewhere between $30 million and $35 million battling Bevin in the primary and Grimes in the general election.

Speaking of Grimes, she has never raised anything close to the amount of money we are talking about. But she has the best fundraising tool any Democrat in the country could hope for: Mitch McConnell.

Democrats loathe McConnell — his comment that “the single most important thing we want to achieve is for President Obama to be a one-term president” became a rallying cry during the 2012 presidential campaign — and they will be more than ready to give to whoever is running against him.

So, how much is that? The closest analogue to Grimes’s situation is that of Sharron Angle, the Republican nominee who took on Senate Majority Leader Harry Reid (D-Nev.) in 2010. Angle, who raised next to nothing to win the Republican primary, wound up spending $28 million in her unsuccessful challenge of Reid. (Reid spent $31 million.)

Angle had no organization and was viewed skeptically by the party establishment. She was the party’s third choice. But Grimes was encouraged by the national party to run, and she comes from a politically well-connected family. (Her father, Jerry, is a former state party chairman and a close ally of the Clintons.)

Given all of that, it’s not unreasonable to think that Grimes’s fundraising floor in the race is around $25 million and that her ceiling could well be over $30 million.

If you assume — and it’s not that much of a stretch — that McConnell spends $35 million, Grimes spends $30 million and Bevin spends around $5 million, that’s $70 million before a single cent is spent by any outside group. And those groups will spend a lot more than that.

Consider the two national parties. The National Republican Senatorial Committee will spend almost everything it has to bring McConnell back, given his prominence within the party and the amount he has done for the committee over the years. And, while the Democratic Senatorial Campaign Committee has plenty of its own incumbents to defend, beating McConnell might make up for lots of other losses in other places, and the committee knows it. It’s easy to see both the NRSC and the DSCC spending in the neighborhood of $10 million each — and that might well be conservative — on Kentucky. Add that $20 million, and the cost of the race is already at $90 million.

The final piece of the spending puzzle is the super-PAC world. A pro-McConnell super PAC — Kentuckians for Strong Leadership — brought in more than $1 million in its first four months of existence. There will be much, much more where that came from. And it’s a certainty that Democrats will set up a super PAC of their own to support Grimes/beat up McConnell. Aside from those quasi-official super PACs for the two candidates, there will be lots of other interested parties who want to make their voices heard — read: spend money in the most high-profile Senate race in the country. Will all of these groups combine to spend $10 million? Um, yes.

The one caveat to all of the above: This race will test just how much money you can spend in Kentucky on a political campaign. As one veteran Democratic strategist noted to us, it’s possible that Kentucky radio and television stations will simply run out of inventory; there, literally, won’t be anything left to buy with all the money pouring into the state.

Maybe. But money the likes of which we have never seen before will be spent in the Bluegrass State over the next 15 months. The $100 million Senate race is upon us.