Trump, Cruz clash over White House eligibility in tense Republican debate

U.S. Republican presidential front-runner Donald Trump and top challenger Ted Cruz clashed sharply on Jan. 14 over the Texas senator's eligibility to run for the White House during a tense debate weeks before voters start to pick the party's nominee. 

Businessman and reality TV star Trump said Cruz's path to the presidency was in question because he was born in Canada. The U.S. Constitution mandates that only "natural born" citizens can become president of the United States. 

Cruz, who was born in Calgary, Alberta, to a U.S. citizen mother and a Cuban father, accused Trump of bringing up his birthplace simply because Cruz was leading some polls in Iowa,   which holds the first nominating contest on Feb. 1 in the run up to the November general election. 

Cruz said Trump, who led the movement questioning whether the Hawaiian-born President Barack Obama was really from the United States, had asked his lawyers to look into the issue of Cruz's birth in September and concluded there were no issues. 

"Since September, the Constitution hasn't changed, but the poll numbers have," Cruz said. "And I recognize that Donald is dismayed that his poll numbers are dropping in Iowa, but the facts and the law here are really clear." 

A Google snap poll showed viewers believed Trump, who in the most recent debates was at times less engaged, won the night with 37.3 percent to Cruz's 26.6 percent and Rubio's 12.1 percent.

Until the Fox Business Channel debate in North Charleston, South Carolina, Trump and Cruz had been friendly because they have both been chasing conservatives of the Tea Party movement and did not want to anger them.

Trump said Democrats would sue if Cruz were on the Republican ticket, putting their party's...