With Mayor Julian Castro enjoying relatively smooth sailing toward his Senate confirmation for the HUD Secretary gig, some mayoral hopefuls are feeling more emboldened. Last week current state Representative Mike Villarreal sent a fundraising email confirming his decision to trade the Pink Dome for a shot at City Hall, meaning he will resign from the Legislature to campaign for mayor. While that bold decision may spell victory for some, it’s worth remembering that Villarreal has hardly faced a contentious race since winning a special election for his District 123 spot in 2000. His general election percentages have sat at above 60 ever since. While Villarreal would almost certainly pursue Castro’s education and Downtown focus, voters tired of big ticket center city projects may be tempted by District 8’s Ron Nirenberg. Unlike Villarreal, Nirenberg recently emerged from a hard-fought 2013 election to become a thoughtful and energetic city council member. While his centrism is unlikely to get the blessing of Manuel Medina’s Bexar County Democratic Party (though City Council positions are technically non-partisan, Medina recently laughed that off in a column written by Express-News’ Brian Chasnoff), his skeptical stance on the streetcar plus his determined work to save the Bracken Bat Cave and to close SA’s so-called digital divide might sway voters looking for a less “establishment” candidate.