Former Massachusetts governor Mitt Romney has clinched the Republican presidential nomination.
U.S. news agencies project Romney will score a big win in the Texas primary, with more than 150 delegates at stake. This will give him more than the 1,144 delegates needed to secure the nomination.
Republicans will hold their convention in Tampa, Florida in August to officially pledge their delegates to Romney and his eventual choice of a vice-presidential running mate.
After losing the Republican race four years ago to John McCain, Romney overcame tough challenges from a raft of challengers, including Newt Gingrich, Rick Santorum, Rick Perry. They questioned Romney's credentials as a conservative, saying he is too moderate 。
Recent polls show him in a virtual tie with Mr. Obama。