(Reuters) - Republican presidential candidate Ted Cruz pledged on Tuesday to boost the size of the U.S. armed forces and invest in new airplanes and ships, as he seeks to push back in military-focused South Carolina against rivals’ criticism of his defense record. Cruz, speaking at a decommissioned aircraft carrier in Mount Pleasant, South Carolina, said that if he won the White House he would establish a total active-duty force of 1.4 million people, prioritize constructing new ballistic missile submarines and invest in anti-missile systems. “If you think it’s too expensive to defend this nation, try not defending it,” the U.S. senator from Texas said in a speech unveiling his proposal. Republicans seeking the party nomination for the Nov. 8 presidential election are emphasizing defense issues in South Carolina. The state, home to a number of military bases and retired veterans, holds its Republican primary on Saturday.  Cruz has taken heat from rivals for voting for bills limiting defense spending and for pushing to revamp domestic surveillance programs. He has also argued for scaled-back military involvement overseas, saying the United States should protect its interests but not engage in “nation-building.” Cruz’s Republican opponents have touted their own plans to boost the size of the U.S. military. U.S. Senator Marco Rubio of Florida has called for the Army to be staffed at 490,000 people, compared to Cruz’s proposal Tuesday of 525,000 soldiers.  (Reporting by Emily Stephenson; Editing by Frances Kerry) SAP is the sponsor of this content. It was independently created by Reuters’ editorial staff and funded in part by SAP, which otherwise has no role in this coverage.