If Ronald Reagan was correct that the Republican Party has three parts -- fiscal conservatives, social conservatives and national-security conservatives -- as pointed out in an Associated Press news analysis on Sunday, Mitt Romney and Paul Ryan must unite those three parts this week behind their bid for the White House.Tropical Storm Isaac might be only a small obstacle in their path. The Republican National Convention is scheduled for an inauspicious beginning today in Tampa, Fla., but the day's events have been shifted to Tuesday out of respect for Isaac's approach.Party leaders say the delay won't lessen the convention's message or its impact.The events through Thursday will reintroduce and, in some ways, redefine the Romney/Ryan ticket as the candidates begin the final push for the November election. They know that they, not their opponents, must carefully craft their image and their issues, which the convention spotlight enables them to do.Romney and Ryan -- like nominees of any party in any election year -- will have to articulate their vision for the country even though in some ways it contrasts with the party platform tentatively scheduled for a floor vote Tuesday.The platform draft has strong anti-abortion language, including no exception for rape or incest, a hot-button issue for the highly courted women's vote. Romney is on record opposing abortion except in cases of rape, incest or danger to the mother's life.The platform proposes more punitive immigration laws like refusing federal funds to colleges that offer in-state tuition to illegal immigrants. Romney is trying to shape his appeal to Hispanic voters.With limited broadcast network television coverage, Republicans must use convention time wisely to get their message on "fixing" the economy to the largest audience possible. Extended coverage will come from cable television and social media.The Romney/Ryan team also will try to appease and excite the Tea Party activists and ardent supporters of Texas congressman Ron Paul.They must get their own house in order before going after independents and moderate Democratic voters -- valuable constituencies for November.