If you’re curious what a U.S. drawdown in Afghanistan looks like, search no farther than northern Helmand province. The region was once the site of massive fighting that killed dozens of Marines in Sangin district alone in fall 2010. Musa Qala, Kajaki and Now Zad districts also have seen their fair share of violence and casualties. Since spending a fair share of the fall in Helmand, the battalion in northern Helmand rotated. Second Battalion, 7th Marines, out of Twentynine Palms, Calif., replaced its sister unit, 1st Battalion, 7th Marines. Lt. Col. Donald Tomich discussed the battalion’s deployment with me recently,…