“After months of hedging, New Jersey Gov. Chris Christie is giving serious thought to jumping into the ring for a GOP presidential run — and could make his decision next week, The Post has learned.

“The announcement may come as soon as Monday, said sources familiar with Christie’s thinking…

“[W]hen the governor first arrived at the Reagan library, he was still telling his inner circle he was a definite ‘no’ for a presidential run — and planned to make that clear in his appearance.

“Something changed that night, sources said…

“Insiders say Christie is ready to put a presidential campaign together ‘pretty fast.’

“And he’d have to, since filing deadlines for key primary ballots are just weeks off.”

“With all the clamoring for Chris Christie to get into the presidential race at this late date, how realistic is it for him — should he decide to run — to pull together a serious campaign in the eleventh hour?

“There are organizational issues, of course, but the main answer, say leading political consultants, lies in ballot access: getting his name on the Republican presidential primary ballot in all 56 of the states and territories by each of their different deadlines. Those start cropping up in just one month — Oct. 31, when filing materials are due in Florida.

“An additional challenge is that each of the 56 contests has different rules with different deadlines, and the process can be time-consuming, aggravating and expensive…

“Election lawyers, however, say it’s still possible for a late-entering candidate, such as Christie or Sarah Palin, to get ballot access in each state and territory.”

“After Super Tuesday and a few other smaller Southern primaries in March, the calendar almost entirely favors Romney – March 20 is Illinois, and April 24 is slated for a slew of Northeastern states that will almost all go to Romney. (As a Northeastern governor, the same math would likely apply to Christie)…

“But the Romney camp also has had a hand in crafting the calendar. Aides like longtime RNC member Ron Kaufman were on hand to keep an eye on the process, and the former Massachusetts governor’s allies continue to try to tweak the calendar around its edges, and to move up Romney-friendly states…

“The calendar’s design, especially the somewhat less than Super Tuesday, suggests that the race may not be decided by early March. The possibility of a Barack Obama-Hillary Clinton, 50-state showdown is certainly present—and the chances of the GOP picking a nominee in April or May is just as likely.”

“This is a serious decision, and I’m engaged in serious deliberations. And within the next 24 hours don’t look for me to make a decision.”