My readers will know that, previous to this mailer, I have written two articles about this very issue, that of partisan politics in a non-partisan race. Does it have a place in this current mayoral race? To summarize my other two posts in three-words: absolutely, positively, and yes. This mailer isn’t about a smear campaign to discredit Curtis as an individual because he happened to run as a Democrat, then a Republican, and is now trying his luck at a non-partisan race; this is about a track record of honesty and sustaining core values. To flip-flop between the Democratic and Republican parties in the State of Utah is more than enough to raise a few eyebrows, but what Steve Clark is asking the people of Provo is simple: “What does John Curtis stand for?”
I invite you to read or re-read my two posts A Tale of Two Curtises and Dramatic Shift to the Right or Left for more detailed information about this issue. I also invite you to read Mr. Curtis’ explanation about why he feels this is not an issue on his website under the ‘Rumors’ section. Yet he still, in my mind, has not explained sufficiently why he made such drastic moves, as failing to gain public office in two different parties and trying your luck at a non-partisan race is more than curious. In summary, this curiosity comes from Mr. Curtis openly contradicting himself about his political background, as is shown below:

“I am running as a Utah County Democrat because the changes to the 2000 platform have brought it into close harmony with my core values.” [1]

"I've been a Republican my whole life...I joined a dramatic attempt to align the Utah County Democratic Party with Utah County values...My values have never changed. My beliefs have never changed." [2]
Two different stories, two very different backgrounds. There is no smear campaigning going on because Steve Clark is concerned about a candidate who is trying to jade his political background by openly deceiving the public about his positions, beliefs, and values. Let us remember that it wasn't Steve Clark who brought the issues of party politics into the fray, it was John Curtis trying to 'clear the air' about his political background. Just like in the court, Mr. Curtis, if you bring in evidence in an attempt to bolster your case, then you give your opposition the right to use it, also. People of Provo, which story are you going to believe, or are you going to allow Mr. Curtis to tell multiple stories about his political background and values? The choice is yours.
[1] http://www.ourcampaigns.com/cgi-bin/r.cgi/CandidateDetail.html?&CandidateID=13693
[2] http://www.deseretnews.com/article/650219973/2-vie-for-Provo-House-seat.html