TRENTON — The 2016 presidential election doesn't have a single declared candidate. But there are many Republicans and a smaller list of Democrats who routinely top the lists of possible White House hopefuls.

Among them on the GOP side is New Jersey’s Gov. Chris Christie.

He’s declared a nationwide run isn’t anywhere on his mind and that when the time comes to make a decision — possibly by the end of the year – he will discuss the matter with his family and then let the rest of us in on his decision.

However, not all political observers — Republican, Democratic and nonpartisan alike – appear to take the governor as his word.

He’s laying the groundwork for a presidential campaign, they say.

Former New York City mayor and GOP presidential candidate Rudy Giuliani had this to say when discussing Christie’s recent travels as chairman of the Republican Governors Association last week : “I don’t see it as a decision that he’s running. I see it as a decision he’s decided against not running.”

Here’s a quick list of clues indicating we may expect to see New Jersey’s governor on the 2016 president circuit:

1. Iowa and New Hampshire

It goes without saying Iowa, which holds the first presidential caucus, and New Hampshire, home of the nation’s first presidential primary, are eyed by every presidential hopeful. But when Christie travels to the states as RGA chairman — twice so far to New Hampshire with promises of a third trip and once to Iowa with another in the works before the November election — he promises it has nothing to do with a presidential run.

However, with Christie declaring recently the RGA doesn’t “pay for landslides” or “invest in lost causes” when explaining why he isn't stumping for the Republican challenging New York Gov. Andrew Cuomo, Christie is campaigning for a New Hampshire Republican gubernatorial hopeful trailing by double digits in a “safe Democrat” race (according to political campaign watchdogs) . And he’s lending a boost to the campaign of a five-term governor in Iowa who enjoys a high approval rating and a double-digit lead over his Democratic opponent.

Political observers say it's because he's laying the groundwork and making inroads with party establishment in those states that could benefit a presidential bid.

In Giuliani’s words: “If you want to be a contender, you got to start doing it now,” he says. “John McCain won (New Hampshire) in ’08 because he spent more time there than anyone else, including (Mitt) Romney, who lived there. So I think Chris is looking at that and saying, ‘If I want even keep the door open to running I’ve got to spend a lot of time there.’”

2. Mexico

Not all of Christie’s out-of-state travel is under the auspice of stumping for GOP candidates as RGA chairman.

Christie will travel to Mexico next month for what’s being billed as a diplomatic and trade mission, but to some is another indication he is laying the groundwork for 2016. The trip comes as a handful of the other potential GOP presidential hopefuls work to make inroads with Latino voters and as immigration dominates national headlines with waves of undocumented children from Central America pouring over the border from Mexico into the United States.

Only a trade mission?

"I don't think anyone will ever buy that at this point," says Julian Zelizer, a presidential historian at Princeton University. "At the state level there is still some connection to the (New Jersey) population and state economy. But I don't think anyone is going to look at a trip like this and not consider his desire to run."

3. Attacking President Obama

Speaking of immigration, Christie has been no shrinking violet when it comes to grabbing an opportunity to lash out against the country’s current commander in chief. Christie criticized Obama for his refusal to visit the United States’ southern border with Mexico (calling it “an indication of (his) unwillingness to lead”) and claimed a short time earlier Obama “dropped the ball” on Israel-United States relations.

The governor has stopped short of offering his own solutions to the country’s immigration conundrum, but his opinions on issues that have implications well outside New Jersey’s boundaries are routinely voiced.

4. Courting GOP donors

Whether it’s hosting special guest Mitt Romney for a NJ GOP fundraiser being billed as a birthday celebration for the governor, meeting Iowa and New Hampshire fundraiser during RGA travels or attending a Republican National Committee fundraiser next month in New York that includes other Republican heavy hitters, Christie is getting serious face time with GOP donors.

To be clear, his duties as chairman of the RGA, which works to elect GOP governors nationwide, require him to fundraiser for the party (and the group has boasted raising record amounts with Christie at the helm). However, if Christie mounts a national campaign, the GOP donors and connections he made along the way will be critical to a successful campaign.

5. The circuit

In New Jersey and on the national stage, Christie is on the circuit.

During his first term as governor he attracted the national GOP spotlight when he helped lead a push to overhaul the state’s pension and health care benefit reforms. And now he’s back at it. New Jersey’s economic woes spurred Christie to renege on a promise to make a full pension payment while balancing the most recentstate budget. Now, the governor is touring the state on his “no pain, no gain” tour telling residents that unless lawmakers act, the state is headed toward dark economic times. He promises to unveil a pension plan by the end of thesummer that could help bolster his GOP bona fides.

Christie’s also been busy delivering speeches in Washington D.C. , where he touted his pro-life philosophy during the Faith and Freedom Coalition’s “Road to Majority” conference in June , and New York, where in May he spoke at the Champions of Jewish Values International Awards Gala before a crowd of 700 people, including billionaire campaign donor Sheldon Adelson.

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