Maricopa County Sheriff Joe Arpaio believes that a media conspiracy "bigger than Watergate" is purposefully downplaying his volunteer posse's investigation of President Barack Obama's birth certificate.

Arpaio and the posse held an hourlong news conference earlier this month describing their belief that the online version of Obama's long-form certificate is a fake. Arpaio began investigating at the request of the Surprise Tea Party. Its members had listened to a speech on the subject by a writer from the anti-Obama, conspiracy-theory-laden website WorldNetDaily (which once published a six-part series of commentaries under the headline "Soy is making kids 'gay' ").

"The media all came to make fun of me," the sheriff said of his "birther" news conference. "I'm a little concerned that all of their questions were zeroed in on credibility and that this has been rehashed. They didn't even ask about the proof of the case. They didn't ask about the facts that we had."

I suggested that perhaps it is because most people believe questions about the document have been answered. In addition, Hawaiian officials have verified Obama's citizenship.

Arpaio is unconvinced.

He believes that the experts used by his volunteers are correct and, while not directly accusing officials in Hawaii, said, "You know there's corruption everywhere. I'm not saying they're corrupt. I'm not saying they're lying. But we have to look into it."

The sheriff is contemplating his next move, which he said could involve taking his findings to law-enforcement officials in Hawaii or Washington, or working with local legislators.

"I'm not going to drop this," he said. "You don't think I did a press conference and let it die? I'll make a decision real quick where to send the evidence we have. There are not many options. You do know this is complex. Many conflicts of interest from the White House to the attorney general. I can go on and on."

Of course, while Arpaio says we should be suspicious of federal authorities, he sees no reason why anyone would question his motives, even though the sheriff has been in conflict for years with the U.S. Justice Department, which now is negotiating with Arpaio's attorneys over how to address alleged widespread discrimination in his office.

"I don't care about the politics," the sheriff told me. "That has nothing to do with it."

I'm guessing politics had a little bit to do with the decision by Republican state Rep. Carl Seel, who appeared at Arpaio's birth-certificate news conference, to introduce a bill in the Arizona Legislature that would require political parties to file an affidavit swearing under penalty of perjury that their presidential and vice-presidential candidates were born in the U.S.

If approved, the law would allow any voter in Arizona to challenge the affidavit, opening up the possibility that the birth-certificate controversy could end up in court.

The sheriff believes something like that would force the media to end its "cover-up."

Arpaio is even having trouble with right-leaning media like the conservative National Review, which published an editorial about Arpaio's latest escapade that read in part: "Republicans who have chosen to associate with the birthers have done their party and their country a disservice. And as Sheriff Arpaio settles comfortably into that political mental ward, the same must be said of those Republicans who choose to associate themselves with him more broadly. Those who cannot distinguish between the birthers' flim-flam and the critical questions that face our nation in 2012 will not win and do not deserve to."

As we all know, there are plenty of incubating eggs in Arizona's political cuckoo's nest. Arpaio promises that this one is going to hatch.

"Donald Trump wrote me a note thanking me for what I'm doing," the sheriff told me. "Everywhere I go people say, 'Thank you, sheriff.' Every speech I give, which is quite often, they say, 'Thank you, sheriff.' To conclude this thing I'm going to get dramatic."

Reach Montini at ed.montini@arizonarepublic.com or 602-444-8978.