Washington (CNN) A week ago today was the last chance to file your 2016 federal income tax returns -- a time which, in the past, has occasioned the president to release a portion of his own taxes.

Not this year.

I only know this because my former Washington Post colleague Callum Borchers noted it in a terrific piece that I had missed until this morning. Wrote Cal:

"Among dozens of questions posed to Trump during an impromptu news conference in the Rose Garden [last] Monday were several about tax policy but none about his own filings, which were, at one time, hotly pursued by the media."

I did a quick bit of work on Google Trends to see how often "Trump tax returns" turns up.

Here's the last 90 days of search for those three words:

And here's the last year -- by week:

Other than that small blip, however, both charts show the same thing: People have stopped asking or caring about Trump's taxes. Which means Trump's gamble is paying off.

Remember that Trump is the first presidential candidate in modern history to refuse to release any of his tax returns. He is certainly the first president to refuse to do so. And, his explanations for why he won't release his returns has been somewhat inconsistent.

Trump himself has insisted that he is under audit by the Internal Revenue Service and, therefore, can't release his tax returns. That's not technically true; Richard Nixon released his 1973 return while under audit

In January, White House senior counselor Kellyanne Conway offered a different explanation of the tax return question. Here's what she said:

"We litigated this all through the election. People didn't care," she said. "They voted for him, and let me make this very clear: Most Americans are very focused on what their tax returns will look like while President Trump is in office, not what his look like. And you know full well that President Trump and his family are complying with all the ethical rules, everything they need to do to step away from his businesses and be a full-time president."

While it's impossible to prove Conway wrong, it's also impossible to prove her right. While Hillary Clinton did make an issue of Trump's tax returns (or lack thereof) during the campaign, it was not the central thrust of her attack on Trump. And, the exit polling -- unfortunately -- didn't ask any questions about Trump's tax returns.

Regardless, neither the audit nor Conway's election explanation seem like the real reason Trump is so resistant to releasing any of his taxes. My belief is more politically calculating and simpler: Trump made the decision way back in the campaign that what was in his taxes was more politically damaging than the heat he would take for not releasing them. So, he didn't release them. ( I wrote a piece for the Post in my former life with 6 possible problems in Trump's tax returns .)

Trump bet on the idea that the average person didn't care all that much about his taxes -- at least not enough to vote on the issue -- and that the media would, eventually, lose interest in asking the same questions over and over if he just never gave an inch.

That appears to be the right bet -- even as Congress prepares to take up a tax cut proposal.

CNN poll released last week showed that 67% of Americans think Trump should release his tax returns -- down from 74% in January. The drop is most marked among Republicans; 51% said Trump should release his returns in January as opposed to just 38% who say the same now.

In introducing the broad outlines of his plan last month, Trump insisted the legislation wouldn't benefit him personally. "Our framework includes our explicit commitment that tax reform will protect low-income and middle-income households, not the wealthy and well-connected," Trump said. "They can call me all they want. It's not going to help. I'm doing the right thing, and it's not good for me. Believe me."

We have no choice but to do so since Trump continues to refuse to give even the most basic peek into his tax returns.

As the tax debate heats up, Democrats on Capitol Hill will likely ramp up their calls for Trump to releases his taxes. But, if Trump only needs 51 votes to pass the bill and Republicans continue to remain mum about his own taxes, all of Democrats' carping won't make a bit of difference.

He'll have won on the issue. Again.