As Election Day fast approaches, the Hampden County DA’s race is being reduced to a fight over Steve Buoniconti’s refusal to release his personal tax returns. And it looks like Buoniconti has no one to blame but himself.

Buoniconti has described all the attention on his tax issue as a “smear campaign” that detracts from the more pressing issues that voters should be considering. Buoniconti, perhaps, should be careful what he wishes for; it’s unlikely he’d come out ahead in a resume-to-resume comparison between him and his opponent, Mark Mastroianni, a former ADA and veteran defense attorney. Buoniconti’s claim that his detractors have resorted to mud-slinging also rings rather hollow given his recent attacks on Mastroianni for serving as a defense attorney. (“He tried to get people out early. Represented the most notorious gangsters and criminals,” Buoniconti—who himself has done defense work—charged at a candidates’ debate.)

Mastroianni makes a valid case that his rival’s tax information is, indeed, a key issue in the race, thanks to some blunders on Buoniconti’s part. First came the revelation, in the Springfield Republican, that Buoniconti, who’s served in the state Legislature for the past 15 years, failed to report on state ethics forms income he earned from a side job working as an attorney for the county pension system. In the wake of that controversy, Buoniconti vowed to release tax information, to satisfy public curiosity about his income sources. Shortly after, the senator released a letter, signed by his accountant, listing his and his wife’s income and tax payments over the past three years—disclosure that fell far short of the complete tax returns Mastroianni and others, including a couple of Buoniconti’s former foes for the Democratic nomination, insist he’d actually promised to release.

Buoniconti cites privacy concerns—specifically, his wife has been a victim of identity theft in the past—to explain why he’s not releasing his actual tax returns. (Never mind that a nice thick Sharpie could be used to ink out any information, such as Social Security numbers, that he, quite reasonably, might want to keep private.) That decision leaves unanswered questions about why Buoniconti and his wife paid what seems like a low amount in taxes, given their total income. It also allows Mastroianni, who did release his tax returns, to portray himself as the full-disclosure candidate—and to raise the question of whether his opponent, if elected, would really offer the kind of transparency and trustworthiness the DA’s job requires.

The Republican, apparently, has answered that question with a big fat “no.” In today’s edition, the newspaper’s editorial board endorsed Mastroianni, citing Mastroianni’s professional qualifications and Buoniconti’s relative lack of experience in the courtroom. But the paper also cites the tax-return controversy, writing that Buoniconti’s caginess on that issue is “not the right attitude to bring to a job that requires a high degree of transparency. While we don’t believe that a district attorney should ever have to tip his hand in a case, the public has the right to have a reasonable amount of information about how investigations and prosecutions are progressing—especially as it affects their safety and sense of well being.”

Today’s endorsement is a rather dramatic turn-around from the Republican’s endorsement of Buoniconti in the Democratic primary last month. (Mastroianni, who is running as an independent, sat out that contest.) While the newspaper said in today’s endorsement that “troubling” questions about Buoniconti’s “openness” have cropped up since the primary, it was, in fact, the Republican’s own reporter, Jack Flynn, who had broken the news about the candidate’s ethics filing omissions, 11 days before the first endorsement was published.