I was 180 degrees from this opinion, two months ago. I insisted the Dodgers shouldn’t trade for Manny Ramirez.

Then, when it happened, I suggested the Manny trade would be the last desperate and foolish act on Ned Colletti’s resume.

A day later, I rounded up the commentary from Boston, where angry/enraged columnists accused Manny of every sin short of war crimes.

Now, I’m going in the other direction.

I was wrong.

The Dodgers should have traded for Manny, particularly considering they gave up very little for him.

And now I believe they should sign him. For years to come. Keep him.

For several reasons.

1. The man can hit. The end. He’s 36, sure, but he still puts up numbers, the sort of numbers the Dodgers desperately need in the middle of their lineup. The man just hit 37 homers with 121 RBI this season, including 17 homers and 53 RBI in 53 regular-season games with the Dodgers.

The Dodgers were punchless before he showed up, averaging 4.2 runs a game. They averaged 4.7 runs per game after he arrived, and a jump of a half-run a game is huge.

2. He brings excitement/interest to the club. In good times or bad.

The Dodgers had turned into a dull franchise and a very dull team. A bunch of maybe-stars among their young guys, a couple of crabby, fading standouts, among their old guys, and really nobody the average fan would go out of his way for to see play.

Manny changes that. He is, it now is clear, one of the great “what’s he gonna do next?” guys of this era.

Will he hit one in the seats? Turn a routine fly ball into a heart-stopping fright show? Topple over in the batting box because he’s got 25 pounds of pine tar on his batting helmet? Will he choose to run out this ground ball, or see if he can break Bengie Molina’s record for “slowest jog to first base”? With this guy, you never know what is going to happen.

He is entertainment, and the Dodgers have had almost none of that. And dearly need it. Their own version of Kobe Bryant, someone everyone — including non-baseball fans — have an opinion about.

3. He makes players around him better. No pitcher wants to talk the guys hitting ahead of Manny, and that just made a couple of the Dodgers’ kids much better players because they know — they know — they are going to see more strikes.

4. The Dodgers can afford it.

Now, the Dodgers shouldn’t do literally anything to sign the guy. We understand that his time with the Dodgers has been about a salary drive, and it is disturbing that he appears to have, essentially, just decided to be a great player for two months after quitting on the Red Sox in the weeks before he got here. So, no, you don’t give a percentage of the franchise to the man, even if his evil agent, Scott Boras, may ask for it.

And you don’t give him ridiculous years. His current contract was for eight years, with two options years. But he signed that contract when he was 28.

He is 36 now, and I can see three years. Maybe four. But I would prefer three, even if the money is better, year over year — as long is it less over the duration.

Yes, the Dodgers can afford it. Or their fans can. Same thing. Turns out they probably won’t even have to jack up their payroll all that much, if they are prudent.

Consider this: The Dodgers have one season to go to shed the ridiculous contracts of Andruw Jones (two years, $36.1 million) and Jason Schmidt (three years, $47 million), who between then will make about $35 million next year. The Dodgers also could bid adieu — this month — to Nomar Garciaparra and Jeff Kent, who between them made $18.5 million this year.

That is, the Dodgers could sign Manny for three years and, say (gulp) $75 million … and most of the $25 million for Year 1 is recouped by getting Nomar and Kent off the books. And the next two years are in large part paid for by the departures of Jones and Schmidt.

And think how many Manny jerseys the Dodgers will sell! And Manny wigs. And how many tickets to people specifically interested in coming to see Manny play.

I’m thinking Manny has at least another couple of good years in him. His production over the past few years is down a bit, from his prime (20 homers in 2007?), but he still instills fear in every pitcher in baseball. And even in a third season here, if he were, say, out of shape or hurt, and sulking, he would still be a lightning rod for attention. And that is worth money to a franchise. The chatter a player can engender.

The way this likely will turn out? The Yankees will sign Manny, because they need another hitter and because they know it will tick off Red Sox Nation. The Yankees probably will out-bid the Dodgers, and we should operate under no delusions: Money is what motivates Manny. (And Scott Boras.)

But the Dodgers should give it a shot. A good-faith, serious-money shot. Three years, $75 million. Yes, OK. Four years, maybe $85 million? Too long, but if that’s what it takes … But that should be the outer limit.

I have flip-flopped on this, and that’s considered poor form, especially during election seasons.

But I was wrong. Manny is a keeper. For his bat and for his box-office. Those are extremely valuable commodities.