Distancing himself from his former-president brother and Sen. Marco Rubio, Jeb Bush appeared to reverse course Monday when he said undocumented immigrants should not be given a pathway to citizenship.

The former Florida governor’s comments came on the eve of the release of a new immigration-reform book he co-wrote called “Immigration Wars: Forging an American Solution.”

While many dismissed Bush’s talk as a book-selling ploy, others saw it as a sign Bush is positioning himself for a presidential run in 2016 — a possibility he wouldn’t rule out — by moving rightward.

A few Republicans and some immigration-reform advocates worried Bush could upset politically fragile negotiations in Washington, where Republicans have increasingly dropped objections to a citizenship-pathway for undocumented immigrants.

“A grant of citizenship is an undeserving reward for conduct that we cannot afford to encourage,” Bush wrote in the book with co-author Clint Bolick, a conservative lawyer.

“Those who violated the law can remain but cannot obtain the cherished fruits of citizenship,” they wrote.

Until Monday, Bush had one of the most liberal immigration positions for a conservative leader. While governor from 1999-2007, Bush backed legislation that would have allowed illegal immigrants to get driver’s licenses.

Bush last year had voiced support for a pathway to citizenship for undocumented immigrants, and he tacitly backed it in a 2007 immigration-reform bill pushed by his brother, President George W. Bush.

That bill failed and helped cost Republicans the support of Hispanic voters.

Now Bush’s political protégé, Sen. Rubio – also a possible presidential contender -- has joined a group of eight senators hammering out an immigration-reform bill that includes a pathway to citizenship. Previously, Rubio supported a mere pathway to residency. Bush supports that idea, rather than the more liberal path to citizenship.

Bush, whose wife is from Mexico, has largely remained consistent on immigration.

Bush still supports the DREAM Act, which would give a special citizenship pathway to college- and military-bound undocumented immigrants brought to this country as children.

Also, Bush warns Republicans about the dangers of adopting hardline rhetoric when it comes to immigration.

“Mitt Romney moved so far to the right on immigration issues that it proved all but impossible for him to appeal to Hispanic voters in the general election,” Bush and Bolick wrote.

“Although Romney eventually called for comprehensive immigration reform, a platform that hardened the party’s stance on immigration hung like an anvil around his candidacy.”

It was all too much for backers and advisers to Romney.

At different times during the presidential campaign, Bush made veiled critical references about Romney. Now, Romney backers say, Bush sounds as if he’s adopting the same positions as Romney.

“Where the hell was this Jeb Bush during the campaign?” one angered Romney adviser said.

“He spent all this time criticizing Romney and it turns out he has basically the same position. So he wants people to go back to their country and apply for citizenship? Well, that’s self deportation. We got creamed for talking about that. And now Jeb is saying the same thing.”