With the field for the 2016 nomination nearly filled out, political pundits and prognosticators of all stripes are making their assessments about who is a viable candidate and who is not, which “lane” a given candidate is competing in and who they might be blocking, and how the overall campaign is likely to play out. One prominent forecaster, Sean Trende of RealClearPolitics.com, takes to Politico Magazine this morning to urge a little caution about how much stock to put in …