Feb. 21—HARLINGEN — Hotly contested May 1 elections could shift the balance of power on the Harlingen and San Benito city commissions. In Harlingen, three seats are on the line in one of the city's hottest elections in years. In the race for the District 3 seat, incumbent Michael Mezmar, a financial analyst, faces former City Commissioner Robert Leftwich, a real estate broker. Meanwhile, ...