CBS News Poll analysis by the CBS News Polling Unit: Sarah Dutton, Jennifer De Pinto, Fred Backus and Anthony Salvanto.
A new CBS News/New York Times poll shows Rick Santorum holding a very slight lead over Mitt Romney among Republican primary voters across the nation, but GOP voters increasingly expect Romney to eventually win the nomination.
In the survey conducted between March 7 and March 11, 34 percent of Republican primary voters said they support Santorum, compared to 30 percent for Romney. Santorum's lead falls within the poll's margin of error.
Newt Gingrich was backed by 13 percent of those surveyed - a slight increase in support from the last CBS News poll conducted a month earlier, while Ron Paul received 8 percent, a slight decrease in support. The changes in support for Gingrich and Paul also fell within the margin of error.
The overall dynamics of the Republican nomination battle have changed little in the last month: voters who identify themselves as conservatives remain solidly behind Santorum while Romney receives more support from moderate Republican primary voters.
Evangelicals have been strong supporters of Santorum in many of the nominating contests held so far, and in this poll Santorum leads Romney by more than two to one among evangelicals.
Santorum also leads among supporters of the grassroots tea party movement by a wide margin. Gingrich and Romney are tied for second place among tea party members, each with about half as much support as Santorum.
Regardless of whom they say they'll vote for, however, an increasing number of Republican primary voters expect Romney will eventually become the party's choice to do general election battle with President Obama.
In January, 55 percent of the Republican primary voters polled by CBS News said they expected Romney to clinch the nomination. That number climbed significantly in this new poll to 73 percent.
About half of Republican primary voters nationwide say they could still change their minds about whom to support - but that percentage has dropped from 60 percent a month ago. While there is still room for change in the race, fluidity has decreased as more primary voters have become sure of their candidate choice.
This poll was conducted by telephone from March 7-11, 2012 among 1009 adults nationwide. 878 interviews were conducted with registered voters, including 301 with voters who said they plan to vote in a Republican primary. Phone numbers were dialed from samples of both standard land-line and cell phones. The error due to sampling for results based on the entire sample could be plus or minus three percentage points. The margin of error for the sample of registered voters could be plus or minus three points and six points for the sample of Republican primary voters. The error for subgroups may be higher. This poll release conforms to the Standards of Disclosure of the National Council on Public Polls.