Watching Mitt Romney discuss his willingness to disclose his tax returns, it’s been hard not to marvel at the rapid evolution. It was only about a month ago when he was asked whether he’d release his tax returns, and Romney replied, “I doubt it.”

About a week later, he said he’d “consider” disclosure. Then he was “not opposed” to releasing the materials. That was followed by his willingness to “probably” disclose. Two days ago, Romney came around to saying he will release returns, but not until April — after, presumably, he’s wrapped up his party’s nomination.

This morning, after the issue has taken a considerable toll on his campaign, Romney gave up entirely on the position he took as recently as late December.

Mitt Romney says he’ll release his tax 2010 tax returns and 2011 tax estimates Tuesday and says it was a mistake for his presidential campaign to hold off as long as it did in getting them out.

He says the attention paid to the issue had become a distraction for his campaign and he’s acknowledging it wasn’t the best of weeks for him.

Romney told Fox News’ Chris Wallace this morning, “Given all the attention that’s been focused on tax returns, given the distraction I think they became in these last couple of weeks, look, I’m going to make it very clear to you right now Chris, I’m going to release my tax returns for 2010, which is the last returns that were completed. I’ll do them on Tuesday of this week. I’m also at the same time going to release an estimate for 2011 tax returns. So you’ll have two years, people can take a good look at it.”

A little disclosure is clearly preferable to no disclosure, but this isn’t exactly evidence of a candidate embracing a model of transparency. For one thing, Romney will release these materials on Tuesday — the day of the State of the Union. It’s almost as if the campaign is trying to pick a time when the tax materials will generate as little attention as possible and when the aides know the political world’s focus will be elsewhere.

For another, notice that Romney is releasing returns for one year and an estimate for another. That’s just about the minimum, and there’s no reason for anyone to accept such a limited look into the candidate’s finances.

As Ben Smith put it, “Releasing the 2010 returns is just blood in the water. What about the previous 20 years?”

When Barack Obama ran in 2008, he released returns for the previous eight years. When Bill Clinton ran in 1992, he disclosed 12 years. As we were reminded on Thursday night, when George Romney ran, he set “a groundbreaking standard,” releasing 12 years of returns. He said at the time, “One year could be a fluke, perhaps done for show.”

And once Mitt Romney’s accounts are done scrubbing, he’s only willing to go back to 2010? That’s just not enough. There are too many questions about his tax rates, investments, and Bain-era finances to end the controversy with such limited disclosure.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.