By JOE VARGO and MICHELLE L. KLAMPE, The Press-Enterprise
U.S.-Mexico border improvements discussed
SAN DIEGO -- The observation posts are vacant, the National Guard helicopters that flew along the U.S.-Mexican border silent, the hammers and welders that beefed up the international boundary fence still.After two years of a historic mission to strengthen the country's southern frontier and boost U.S. homeland security, members of the California National Guard are going home.

