I am a fellow Republican, and I have been since I was old enough to know the difference between the parties. To me, that difference came down, more than anything, to trust. We trust our officeholders to make appropriate choices and use their best judgment; and politicians trust us to take the long view and wait out the passions of today. In short, you do what you need to do, and we give you the time and support to do what must be done. By that standard, we have trusted you all along; but when push came to shove, you did not trust us.
I do not care, could not care less, if you are straight or gay, so long as you live up to your word and up to your responsibilities. It is simply none of my business. Most Republicans I know or are acquainted with share a similar view. We truly do not care what you do in your private life, so long as you hurt no one, break no laws, and keep our interests firmly in mind during the day. Sadly, this you failed to do. By being arrested in the manner that you were and by pleading guilty to ANY charge, even a lesser one, you accepted that your actions, in a public setting, were wrong and actionable. You broke the compact.
I see no way for you to come through this experience with credibility intact, either at home here in Idaho or in Washington. These are troubling times in need of character and steadfast resolution, and hairsplitting about whether you should have done this or ought to have done that serves no purpose save your own ambition and sense of vindication.
A number of years ago, Senator Packwood chose to resign under circumstances involving sexual/public misconduct. There was no "proof" in his instance, either, and he was plenty steamed when his hometown paper, the Oregonian, printed page after page of allegations. In the end, there was nothing for it but to leave, and he chose to exit as gracefully as he could. Senator Adams of Washington, when faced with worse allegations, refused to run for re-election.
Senator, I hope that you will see fit to free the party and the Senate from a full consideration of your case. I know that it hardly seems fair to you on a certain level, and that your instincts, as mine would likely be—initially— are to fight back hard. But this is a battle you cannot win. In the end, I think you will decide that you will have to take one for the team.
Resignation now would allow Governor Otter to appoint your successor, who would then have a prohibitive advantage in retaining the seat. It is likely that, even in the event you choose to remain and not run for re-election, the seat will stay in GOP hands. But if you run for re-election as vindication, you will almost certainly lose. Over 40% will vote against you as a starting point, simply because you are a Republican. And you cannot count on more than 50% of the Republican vote, because of the allegations and the guilty plea. The Democrats will use you and your troubles in a nationwide attempt to paint Republicans as hypocritical, and will get some traction with the issue. You know that, sir. The strong probability is that you will lose; if you do, the national party will lose as well, and these are serious times when we can ill-afford a filibuster proof Democratic majority in the Senate.
I take no joy in this because I respect the work you have done on behalf of Idaho and the Nation, but for the sake of the Republican Party—and, more importantly, for the sake of Idaho and the US—I respectfully urge your resignation as Senior Senator from the State of Idaho.