LAS VEGAS — After a likely second-place finish in the Nevada caucuses Saturday, former House speaker Newt Gingrich sought to dispel the idea that he might drop out of the Republican presidential nomination any time soon, promising a hotel ballroom filled with reporters that he will fight on to the convention in the summer.

Republican presidential candidate, former House speaker Newt Gingrich speaks on Feb. 4, 2012 in Las Vegas, Nevada. (David Becker/Getty Images)

Gingrich launched into one of his sharpest attacks ever against GOP presidential candidates front-runner Mitt Romney, signaling that he will continue to hammer on his leading opponent as the nomination moves on to Colorado, Minnesota and beyond — “in every state in the country,” he said. He called Romney “dishonest” and a “Massachusetts moderate,” proclaiming that Republicans eventually will turn against a candidate who, he said, has supported abortion rights, gun control and higher taxes — and then not told the truth about it.

“If you can’t tell the truth as a candidate for president, how can the country possibly expect you to lead as president?” Gingrich said, speaking specifically of Romney’s performance in the most recent debate, in Jacksonville on Jan. 26. “I frankly was stunned. I make no bones about it.”

Gingrich said his plan is to amass about as many convention delegates as Romney by the time Texas votes on April 3. “By that point,” he said, “we can win the nomination.”

He said he brought together his advisers this week in Nevada to figure out how to put that plan into action. He did so, he said, when he realized “the degree to which the establishment has closed ranks and made quite clear that they are desperate over the prospect of a Gingrich presidency.”

“We frankly spent the last four days laying out a campaign for the next four months,” he said. “Although we will be outspent, we believe we can communicate through the clutter.”

Though Romney has won decisively in two states now, only 135 of 2,286 available delegates had been awarded before the Nevada caucuses, meaning the delegate race is still wide open, at least as Gingrich sees it.