Rick Perry's spokesman, Mark Miner, tells The AP that his boss will make the announcement during his Saturday appearance in South Carolina.
When the Perry speculation heated up in June, I wrote a lengthy post on why he could and couldn't win.
Since my analysis -- like The Princess Bride -- is timeless, I'm re-posting it.
Why He Can Win:
Here's the type of video he could trot out -- contrast this with the mess of an economy Obama will have to run on, and you can see why Republicans could get very delighted about a Perry vs. Obama matchup.
That's not such bad stuff, and you can't discredit him by claiming he just inherited a shiny ship. He's on his third term as governor. He's been captain for more than a 3-hour tour.
Also, just today, a new report showed that Texas is responsible for 45% of net U.S. job creation.
If you had numbers like that and had to help out Illinois, you'd probably want to secede, too.
In fact, his record is so good that he won a third term even though more Texans disliked him than liked him, and that's an important point. Perry fatigue is very real in Texas, and a recent poll showed he wouldn't even win a presidential primary there, if the election were held today.
But he was able to beat two very tough opponents in 2010, despite that fatigue.
In 2009, he was losing a GOP primary gubernatorial matchup against Kay Bailey Hutchison by over 20%, and ended up winning by 20%.
How did he come back? By focusing relentlessly on Texas' performance during a sour economy.
And that moves us quickly to a second strength: He's an unbelievably good politician and campaigner. He and his team know how to find an issue, stick with it, and stay on-message.
He also knows how to reach key constituents. When many of his ideological brethren were supporting Arizona's controversial immigration law, he opposed one for Texas -- earning the title of "Most Hispanic-friendly politician in the country" from a Hispanic group.
Hispanics play a crucial role in Texas, Perry knows that, and he also knows that they'll play an increasingly central role in a general election. Like his predecessor -- George W. -- he's a Texas governor who knows how to bring Hispanics into the fold.
Here's something else you might not know -- during the brief "Let's repeal the 14th Amendment" fad, he objected to any sort of tweak.
So even though he has a reputation as an unwavering ideologue, he's well-acquainted with pragmatism. He endorsed Rudy Giuliani, after all, in 2008.
Nearly as impressive as his resounding victory over the popular Hutchison in the 2010 gubernatorial primary was his trouncing of his Democratic opponent -- the well-liked and solidly-named, Bill White.
Pundits breathlessly speculated that White's popularity and Perry fatigue would combine to make it a closer race. It wasn't. Perry killed him by 12%.
National eyes watched all this, and the White House seems to know just how much potential Perry has -- a Democratic strategist close to the Obama White House told CNN today:
"I think absolutely there is a path to victory for him on the Republican side."
His path to victory? Become the tea party candidate who's most palatable to the establishment.
If GOP insiders had it their way, Mitt Romney, Tim Pawlenty, or Jon Huntsman would be the nominee. But none of those has connected with the tea party.
Perry can/does/will/would connect, and while he has a notoriously fractious relationship with the Bush clan -- extending to guys like Karl Rove -- he's much more comfortable schmoozing with the jet set than Michele Bachmann would be.
Perry has the benefit of taking two messages to each key set of the GOP.
1. He can tell the tea party that he's the most conservative candidate the moderates will allow.
2. He can tell the moderates he's the most moderate candidate that the conservatives will allow.
Why He Can't Win:
He's from Texas and talks just like George W. Bush.
Then there's the secession thing.
He never advocated it, but seemed open to it, and when he denied being open to it, he pronounced "secede" as "succeed."
And on his recent book tour, he floated the idea of letting states opt out of Social Security.
Here's a big problem with Perry -- he'll be extraordinarily easy for Democrats to paint as being too extreme for America.
Not only does he say controversial things, but he just seems so controversial saying them.
For example, if John Thune said we were going to bomb Canada, Alanis Morissette would sit coy and stationary.
If Rick Perry said it, she'd call Nelly Furtado and they'd immediately vamoose to a secret bunker where Canada's national treasures are held (i.e. where a gold record of The Crash Test Dummies' "Mmmmmmmmmm" is kept).
Whether it's all bluster (Perry bragged about having shot a coyote while jogging with his dog) or no bluster, at all (he actually did shoot a coyote while jogging with his dog), doesn't really matter. He's just very Rick Perry, very Texas, and very biop-icable.
And that means he's really vulnerable to attacks.
With the economy in shambles, Barack Obama will probably run an extraordinarily negative campaign, and there's nothing he would rather do than run against George W. Bush again in 2012 -- which is exactly what most Americans will see Perry as being.