Indian Country Today: Dene, Cree and Metis activists from First Nations affected by Alberta tar sands development made themselves heard in Washington as Canadian Environment Minister Jim Prentice was making the rounds of Capitol Hill. They hand-delivered a letter to Sen. John Kerry, D-Mass., head of the powerful Foreign Relations Committee, and later about 50 young people from Canada demonstrated outside Kerry’s office when Prentice went in. Clayton Thomas-Muller, Canadian tar sands campaigner for …