Republican presidential candidate, former Massachusetts Gov. Mitt Romney

Mitt Romney is well-known now for flip-flopping on most of the centrist policies he has previously supported -- for example, health care reform, immigration, and funding for safety net programs -- in order to woo hard-right Republicans in his pursuit of the presidency. But when he hired a gay, widely respected foreign policy expert who had long served in the former Bush administration, he must have felt immune to pressure from the anti-gay bigots in his right-wing constituency.

Wrong. After quickly running into pressure against his hire of Richard Grenell from the anti-gay American Family Association, the online Daily Caller and the National Review -- all harsh critics of Grenell's known personal advocacy of legalizing gay-marriage -- Romney abruptly reverted to flip-flopper form.

He had his campaign handlers order Grenell to stay perfectly silent when the foreign policy team that Grenell was hired to head held an international media teleconference last week -- a conference call that Grenell had organized to speak to dozens of national and international media outlets about the difficult foreign policy issues of the day in Syria, China, Afghanistan and other countries.

Grenell, according to news reports, took the hint: Romney wasn't going to support him against anti-gay critics, or allow him to visibly do his job as spokesman for the campaign's foreign policy discussion. After barely a month on the job, he quit.

Romney's advisers now say, The New York Times reported, that Romney and his staff valued the experience and expertise Grenell had gained as the United States spokesman under four ambassadors at the United Nations; that they had really wanted him to stay with the campaign.

Of course, they had undermined his credibility with the media by gagging him in the teleconference, and then by telling him that he had to keep a low-profile to let the dissent of the anti-gay crowd calm down. Grenell had no incentive to stay and work for a candidate who said he valued his expertise but was afraid to let him be seen or heard.

His departure has reasonably angered the GOP's pro-gay groups, the Log Cabin and GOProud members. It hasn't, however, proved Romney's bona fides with the zealously anti-gay critics that didn't like him before, and don't trust him now.

Romney should learn the lesson: Denying his past policies now, under pressure from strident right-wingers, will not fool them, nor will it keep the confidence of voters who previously trusted him. All his reversals prove is that he is a willful chameleon who will change his position to suit the mindset of the people he's talking to at the moment. And if he can't be trusted, if his convictions are superficial, he shouldn't be president.