Continued from page 1

“If we carry Saturday, I think I will become the nominee this fall,” Mr. Gingrich said Wednesday.

Later in the day, Mr. Gingrich tried to undercut the case for voting for former Sen. Rick Santorum or Texas Gov. Rick Perry — the two other candidates seen competing in the primary-within-a-primary for the conservative vote.

“There is one candidate who can give you a conservative nominee and only one candidate who can stop Mitt Romney, and a vote for anyone else is a vote that allows Mitt Romney to potentially be our nominee,” he said.

Rep. Ron Paul, Texas Republican, took the day off from primary campaigning to return to Washington to vote on the House floor against raising the federal government’s borrowing limit.

Looming Thursday night is yet another debate, and Mr. Romney is sure to face renewed questions about his taxes.

In Monday’s debate, he refused to agree to release his tax forms, saying he would revisit the issue in April. But by Tuesday he had changed course and said he would indeed release them later. At the same time, he acknowledged paying a tax rate that he said was closer to 15 percent at which the rate investment income is taxed rather than the higher rates many middle-class families pay on salary or wage income.

Mr. Gingrich told reporters Wednesday he paid income taxes at a rate of 31 percent.

On Wednesday afternoon, ABC News reported that Mr. Romney has up to $8 million invested in funds in the Cayman Islands, which it labeled a “notorious Caribbean tax haven.” The report did not specifically say Mr. Romney was avoiding tax obligations, but stated that the revelation adds to questions about his income and wealth.

Andrea Saul, a spokesman for Mr. Romney, said the ABC report is erroneous.

“ABC is flat wrong,” she said, adding that the investments in the Cayman Islands “are taxed in the very same way they would be if those funds were established in the United States. These are not tax havens, and it is false to say so.”

• This article is based in part on wire service reports. Paige Winfield Cunningham reported from Spartanburg, S.C.