Idaho Falls, ID - Receiving a rock star welcome from thousands of fans, Mitt Romney, in a swipe at both his Democratic and Republican rivals, promised he would never "embarrass" the country,

"What we need in leadership is individuals who will tell the truth and will live with integrity," Romney exclaimed to loud applause during a rally at a local high school gymnasium. "I will not embarrass you in the White House."

The comment was directed at both President Obama - whom Mr. Romney has repeatedly criticized for apologizing to other nations - as well as his Republican opponents, Newt Gingrich and Rick Santorum. The former Speaker is known to have a natural penchant for putting his foot in his mouth, while the former Senator has made comments recently that could be seen as outside the mainstream.

The exuberant crowds - more than 2,500 split between the gym and a nearby overflow room - ate it up, shouting and waving homemade signs with every promise he made. And Mr. Romney, in turn, fed off their energy, seeming more comfortable and fiery than usual.

It was Mr. Romney's largest and most enthusiastic crowd since drawing nearly 3,000 people at a rally in Colorado in February. In a nod to the size, he exclaimed, "this is a far cry from what it was like when I first came to Idaho!"