Cruz: GOP race over in March
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Sen. Ted CruzRafael (Ted) Edward CruzOvernight Finance: GOP criticism of tax bill grows, but few no votes | Highlights from day two of markup | House votes to overturn joint-employer rule | Senate panel approves North Korean banking sanctions GOP criticism of tax bill grows, but few ready to vote against it Anti-gay marriage county clerk Kim Davis to seek reelection in Kentucky MORE (R-Texas) in a private call on Thursday said the GOP race for the White House will probably be decided by March.

Cruz told campaign volunteers on an end-of-the-year conference call to be ready for a month of attacks, predicting a brutal January, according to CNN.

"There is a very good possibility that the Republican primary will be decided by the end of March," Cruz told volunteers during the call. "First thing tomorrow, we've got a 90-day sprint to get the job done."

Cruz is seen as a favorite for the GOP nomination and is leading polls in Iowa. 

Nationally, however, he trails GOP front-runner Donald TrumpDonald John TrumpDems win from coast to coast Falwell after Gillespie loss: 'DC should annex' Northern Virginia Dems see gains in Virginia's House of Delegates MORE, who is also ahead of Cruz in polls of New Hampshire and other states.

Cruz has been enjoying a spike in the polls while garnering critical endorsements and donors to aid his bid.

He was the first to announce his fourth-quarter fundraising haul, raising nearly $20 million in the last three months of 2015. 

The Texas senator has been consolidating evangelical support and securing key endorsements from social conservatives in the first-in-the-nation caucuses state. Iowa voters will head to the polls on Feb. 1.

Cruz is also working to secure a strong placement during Super Tuesday on March 1, when a number of Southern states host contests.

The conservative firebrand also touted the recent flurry of attacks from his GOP rivals: "If we were sitting here on Dec. 31 and no one was attacking us, or looking to be attacking us, I would be deeply, deeply concerned," Cruz said.

Cruz has avoided going negative against Trump, but the Texas senator’s political director, Mark Campbell, said that the GOP establishment is warming up to Cruz and “coming to us as an alternative to Donald Trump.”