DES MOINES -- Republicans in search of their party's presidential nomination are returning to campaign mode after a brief Christmas respite, with Rick Santorum taking a hunting trip with conservatives in Iowa and Mitt Romney phoning supporters.
With just a week until Iowa holds its leadoff caucuses and many voters still undecided, the final push ahead of the Jan. 3 contests was heading into a critical time. Campaigns planned new television ads and phone calls to sway holdouts still weighing their options.
Romney, who kept this state at arm's length for most of the year, seemed to increase his efforts in Iowa as polls found him in a stronger position. He planned to talk with supporters in a series of telephone calls Monday.
Romney planned to deliver a speech Tuesday evening and then set out on a bus tour of Iowa.
Each is running out of time and looking to derail Rep. Ron Paul, the Texas congressman who seems to have the most sophisticated network of volunteers ready to organize ahead of the caucuses. Paul was to return to Iowa this week to meet with supporters he has kept in touch with since his unsuccessful run in 2008.
Candidates were ready to turn on their political machines and had fresh ads ready to air.
Gingrich, who last week criticized the negative tone of the campaign, was preparing to directly challenge Romney on the economy, an issue Romney has made central to his campaign.
Gingrich's standing in public and private polls has slipped as he faced unrelenting criticism from the other candidates and their allies. He was expected to use clips from Romney's previous campaigns distancing himself from president Ronald Reagan and pitch his own economic plan as "Reaganomics 2.0." Gingrich also was expected to compare Romney's tax plan with his own.
Romney released a new TV ad in Iowa Monday that touts him as a conservative businessman and in which he says "it is a moral imperative for America to stop spending more money than we take in."