Cruz, Rubio spar as they ascend polls in Iowa, nationally

DES MOINES - Republican presidential candidates Ted Cruz and Marco Rubio are trying to squeeze through an opening in Iowa.

And they're starting to rub - perhaps even throw - elbows.

Cruz and Rubio, a pair of U.S. senators from Southern states, have been rising in the polls in Iowa, threatening to break the three-month stranglehold of the top spots enjoyed by Donald Trump and Ben Carson.

The most recent poll in Iowa, published this past week by Quinnipiac University, showed Cruz not only overtaking Carson in the second spot but finishing within the margin of error of Trump.

Meanwhile, Rubio has become a steady top-four finisher in polling in the first-in-the-nation caucus state.

As they continue to threaten Trump and Carson's perch atop the polls, the Cruz and Rubio campaigns in recent weeks have turned their sights on each other, perhaps sensing a narrow lane emerging through which a more traditional candidate can penetrate the anti-politician sentiment that has fueled Republican voters this year.

'They're similarly situated,” said Craig Robinson, who publishes the website TheIowaRepublican.com and is a former political director for the state party and field organizer for Steve Forbes's presidential campaign in 2000.

'They're both young. They're both first-term senators. They are both very ambitious. And it's interesting to see them maneuver.”

Cruz, of Texas, and Rubio, of Florida, have much in common. Both were elected to the U.S. Senate in the conservative wave of 2010, both with strong support from self-identified Tea Party Republicans. Both are 44 years old. Both have immediate family roots in Cuba.

And now the two find themselves charging down the same path - the one they hope passes Trump and Carson for the Republican nomination.

'They're both young, they're both articulate, they're both in the Senate with not a lot of experience and both Hispanic. So they have that sort of attraction,” said Tim Hagle, a political-science professor at the University of Iowa. 'Yeah, it's interesting to see how those two have gone at each other because in some sense they sort of represent that same kind of niche, at least in some respects.

'In other respects on the political side, they're a little bit different, where Cruz comes off as a much more conservative candidate, at least in terms of his rhetoric and so forth where he wants to be the fighter, the person taking on the leadership in his own party. Rubio is seen as more the person who can get along with folks and try to get things done.”

Campaign staff for Cruz and Rubio did not respond to a request for comment for this story.

The recent exchanges between the Cruz and Rubio campaigns have centered on immigration and foreign policy.

Cruz has been critical of Rubio's work on a bipartisan immigration reform bill introduced in the U.S. Senate in 2013. Rubio was one of eight senators to craft the legislation, which included a 13-year process for people living in the United States illegally to obtain citizenship.

Rubio since has attempted to distance himself from the legislation, but it remains a sticky subject with many Iowa Republicans who consider allowing those living here legally to achieve citizenship or even legal status akin to granting amnesty. As does the fact Rubio has not ruled out supporting a path to legal status or citizenship after an extended period of time.

Rubio shot back at Cruz over the latter's support for legislation that would have ended the federal government's bulk data collection programs. In the wake of the recent terrorist attacks in Paris, Rubio said Cruz supported legislation that would have weakened the country's ability to identify such attacks before they occur.

And last week, Rubio declared his support for the federal mandate that the nation's fuel supply must contain a certain percentage of corn-based ethanol. The program is popular with Iowa agribusiness, and although Rubio did not mention Cruz when supporting the mandate, he knows Cruz opposes it - along with all federal subsidies.

'I think that, No. 1, a guy like Rubio knows that to be successful, a guy like Cruz has to paint (Rubio) to be the establishment moderate, and so you've seen Rubio actually be very pre-emptive and basically sometimes, like on immigration, painting Cruz as having the same positions that he does,” Robinson said. 'So it's kind of fascinating gamesmanship to watch.”

Although other Republican candidates have had similar surges in the polls only to fade - Scott Walker, Carly Fiorina and now Carson, for example - Robinson thinks Cruz could buck that trend with his superior campaign organization.

'He actually has a campaign on the ground that's working, and he's in the state quite often. That matters,” Robinson said. 'We saw Carly Fiorina move up and obviously Carson, and what ...

(was lacking) in both of those instances was a strong campaign on the ground to sustain it.

'Basically it was a surge in popularity, but they didn't build anything with it. So when the popularity subsided a little bit, there really was nothing left, so those numbers fall back down.

'I think Cruz is running a little bit more disciplined ground campaign in Iowa. So I think that his numbers will stick, maybe, better than some of the other candidates,” Robinson said.

Cruz has made an aggressive play for the vote of Iowa evangelicals, who hold significant sway among the state's Republican voters. Cruz's pastor father has campaigned for his son numerous times here, and Cruz's Rally for Religious Liberty in August drew 2,500 people to downtown Des Moines.

Rubio has portrayed himself as a young, fresh face who can lead the Republican Party and the country into the future.

'It looks like these two will definitely at least be tangling with each other throughout the duration of the caucuses,” Robinson said.