Newt Gingrich
Newt Gingrich's presidential campaign is furious over an ad claiming that he backed a bill in the House of Representatives involving China's "one child" policy. REUTERS

Republican presidential hopeful Newt Gingrich threatened Sunday to have federal judges arrested if they disagreed with his policies as president, ratcheting up his attacks on the judiciary as he tries to halt a slide in his campaign.

I got into this originally because of two things: the steady encroachment of secularism through the courts to redefine America as a non-religious country and the encroachment of the courts on the president's commander-in-chief powers, which is enormously dangerous, Gingrich said on CBS' Face the Nation.

Gingrich has said that, as president, he would ignore Supreme Court decisions that conflicted with his powers as commander in chief. He said on Face the Nation he would subpoena a judge if the jurist disagreed with him, and send police if you had to or you'd instruct the Justice Department to send a U.S. marshal if necessary to bring the judge in.

The tough line against judges may please conservatives who rail against an activist judiciary over issues such as allowing gay marriage rights or limiting prayer in schools. But it could also work against Gingrich since voters already are angry over constant battling in Washington between the White House and Congress.

That's not going to sit well in a seven-second soundbite, said Republican strategist Ford O'Connell. When people hear that, that becomes divisive. And what are people most concerned about now? Divisiveness in Washington.

Gingrich reached the top of the Republican field last month as the favored conservative alternative to former Massachusetts Governor Mitt Romney. But his front-runner status has prompted withering attacks from rivals that he is an unreliable conservative and influence peddler, particularly over fat fees he earned from Freddie Mac, a mortgage giant tied to the economic recession.

Gingrich acknowledged in a call with supporters and journalists that the onslaught is taking a toll. I feel badly about having to have this kind of a phone call just to dispel negative things. As all of you know, I've tried very hard to campaign on a positive basis, he said.

Gingrich was attacked in the Wall Street Journal's editorial page, a leading voice in U.S. conservatism, on Saturday over the $1.6 million in payments he received from mortgage giant Freddie Mac. To wit, he has a soft spot for big government when he can use it for his own political ends, the newspaper said.

Only weeks before the first voting for the 2012 Republican presidential nominee - Iowa's caucuses on Jan. 3 and New Hampshire's primary on Jan. 10 - Gingrich's poll numbers have been slipping.

END OF THE SURGE?

Polls still put him in first place in the race to oppose Democratic President Barack Obama's 2012 re-election bid. But his lead over Romney and Texas Congressman Ron Paul has narrowed.

Gingrich has dropped to 28 percent from 37 percent in Gallup's national tracking poll since the beginning of December. In Iowa, a state many analysts consider an essential win for Gingrich, a range of polls show him slipping from about 32 percent to about 24 percent, still in first place but only just in front of Romney and Paul.

This is a candidate with a lot of baggage and some of the baggage has been chased out by the media and his opponents, and that is having an impact, said Christopher Arterton, a political scientist at George Washington University.

Romney, who lives in neighboring Massachusetts and has a large vacation home in New Hampshire, has an 11 point lead in the state, according to polls compiled by RealClearPolitics.com.

Bob Dole, who was Republican Senate majority leader when Gingrich was House speaker, on Sunday endorsed Romney, adding to a long list of establishment Republicans who have backed the former governor despite concerns by some conservatives that he is too moderate.

Voters are getting signals from sources that they trust, conservative and Republican sources, that that candidate (Gingrich) has flaws, and some significant flaws, said Charles Franklin, a University of Wisconsin political scientist and founder of the website PollsandVotes.com.

Romney also scored a key endorsement on Sunday when the Des Moines Register, Iowa's main newspaper, backed him and took a swipe at Gingrich. Newt Gingrich is an undisciplined partisan who would alienate, not unite, if he reverts to mean-spirited attacks on display as House Speaker.

Gingrich dismissed the endorsement, calling the Register a liberal newspaper. But it underscored his problems in Iowa.

Romney's supporters have been flooding television airwaves and mailboxes in the state with attack ads against Gingrich, while libertarian favorite Paul has been mounting his own challenge to win the upcoming caucuses.

Gingrich also has lagged badly in setting up an organization in the state, which makes its choice for the nominee in hundreds of caucus meetings. To win the caucuses, a candidate needs armies of volunteers to make his case and get supporters out on caucus night.

Gingrich did not help his cause by taking a break from campaigning in Iowa this weekend, when his rivals logged hundreds of miles crisscrossing the state to meet personally with as many supporters as possible.

On Saturday night, Gingrich attended a concert near his home in Virginia where his wife performed with a community band. On Sunday, he appeared on nationally televised Face the Nation rather than on Iowa radio or television.

He needs to be in Iowa... Without Iowa he's in real trouble, O'Connell said. He added that Gingrich, whose fundraising has lagged his main opponents, needs an early victory to attract donations he would need to win the nomination.

With opponents and supporters spending millions of dollars on attacks, Gingrich will need a warchest to fight back as campaigning moves to South Carolina, which votes on Jan. 17 and expensive media markets in Florida, whose primary is Jan. 31.

(Additional reporting by Sam Youngman and Deborah Charles in Iowa, editing by Alistair Bell and Christopher Wilson)