Open thread: Massachusetts; Update: "Cautiously optimistic"; Update: Cook Report analyst calls it; Update: Larry Sabato calls it

We’ve been online at HA for almost four years, yet in all that time we’ve never had a moment like this one. Our debut was in April 2006, six months before the Dems’ takeover, and it’s been all downhill since then. I honestly don’t remember what it’s like to blog really big, really good political news. The closest we got was the killing of the amnesty bill two years ago, but even that zombie may be resurrected to haunt us again this summer. A naturally pessimistic mind weaned on a steady diet of gloomy news simply isn’t built to handle stuff like this.

Rasmussen says he’s been scrambling to put together an exit poll; the data should be out shortly after the polls close at eight. The tears in leftist heaven have been flowing steadily for days and mordant Democratic souvenirs of Coakley’s ineptitude are already on sale. Even the bookies have already started paying out on Scotty B. Bad, bad karma. Live results should be available at the Globe’s site — we already know what they’re hoping for — but I’ll update if I find any better ones.

The moment is at hand. It’s prediction time. I can only be what I am, my friends, and that is an eeyore: Coakley 50, Brown 48. Heart-ache. Exit question: Will tonight see a humpbot cameo or the dreaded melting bunny?

Update: NBC says only about 25 percent of all precincts will be counted by nine p.m., so unless Brown’s really on his way to a landslide, don’t expect a call anytime soon.

Update: For what it’s worth:

Eric Fehrnstrom, Scott Brown’s senior strategist, tells National Review Online that he is “cautiously optimistic” with 50 minutes to go until the polls close. “Our reports show the turnout in GOP areas to be great and in Boston, not so much. The Democratic machine needs to come out for her to win.”

Update: Rasmussen’s numbers are out. Uh oh:

* Among those who decided how they would vote in the past few days, Coakley has a slight edge, 47% to 41%.
* Coakley also has a big advantage among those who made up their mind more than a month ago.

We shouldn’t be seeing that late break given the momentum towards Brown. On the other hand, Rasmussen also sees 22 percent of Dems voting for Brown — which is in line with the polls — and Ben Smith is reporting that a senior Dem on the ground says turnout in liberal and minority districts isn’t as high as they need it to be.

Update: Having a hard time finding live results but Fox Boston appears to be updating semi-diligently. See the right-hand side of the screen. Or see this page at CBS Boston.

Update: A good omen from Twitter: “BREAKING: Scott Brown has carried the bellwether town of Ashland, 54-45. All votes in Ashland are counted.”

Update: A now a bad omen from Sean Trende at the RCP blog: “With 36 precincts — almost 2% ! — Brown is still at 55%-45%. Ashland is in, giving Brown a 54%-45% lead. Romney won it 59%-36%. Unless Brown is putting together a different coalition than Romney’s, he’s in trouble.”

Update: With more than 10% in, Fox Boston says Brown leads by seven.

Update: Another page worth refreshing frequently: House analyst Dave Wasserman’s Twitter feed. He says Brown’s been overperforming thus far.

Update: This bodes well: “You know what’s going to happen.”

Update: Oh my. Patrick Ruffini says a call for Brown might be imminent and Geraghty notes this:

In 2008, Ashland, Massachusetts went for Obama over McCain, 5,039 votes to 3,181.

Tonight Brown won Ashland 54 percent to 45 percent – 3,467 for Brown while Coakley carried 2,897.

You can call it, folks.

Update: Deep breath — Dave Wasserman of the Cook Report says he’s ready to call it for Brown.

Update: Still nothing from any news agency but Larry Sabato says you can take this one to the bank.