HUDSON, Wis. - As he greeted workers at a manufacturing plant and rallied supporters of Wisconsin Gov. Scott Walker, Gov. Christie went to lengths to describe Walker, a potential rival in a 2016 presidential contest, as a friend.

"I will tell you, this one is personal to me," Christie, traveling as chairman of the Republican Governors Association, told a crowd Monday gathered in a Republican campaign field office in this town about 30 miles from Minneapolis.

After noting that his oldest daughter, Sarah, had instructed him to say hello to Walker and Walker's wife and children, Christie said, "That's the way our families are."

Earlier in the day, Walker said that Christie's campaigning on his behalf was "like having a family member in the state with me."

Praising Walker's honesty and integrity, Christie attacked Walker's Democratic challenger, Mary Burke, who has been criticized as a plagiarist for having language and ideas in her jobs plan used by other Democratic gubernatorial candidates. Burke has blamed a consultant who worked for all four campaigns and cut ties with him.

Prosecutors in Wisconsin have been investigating whether Walker's campaign illegally coordinated with conservative groups that have spent heavily in the state.

Christie's support for Walker, who is facing a tight reelection battle and who political analysts say would likely be damaged nationally by losing the governorship, stopped short of a presidential endorsement.

"Gov. Walker is a great governor, and he would do good at any executive position that he wanted to pursue," Christie told reporters. "But I know this much, because I've spoken to him about it - he's not focused on anything beyond Nov. 4, and neither am I."

If the two governors were to run in 2016, their stump speeches could share a theme. Both have focused on reining in costs of public-sector union workers.

But their approaches differed. During his first term, Christie got Democrats who controlled the Legislature to agree to changes that require workers to pay more toward their pensions. The deal burnished his national image as a bipartisan leader, though recently Christie has come under fire from Democrats for cutting state contributions to the pension system.

In Wisconsin, Democrats left the Statehouse in 2011 to avoid voting on a bill Walker had pushed to limit the collective-bargaining rights of workers. The law, which later passed the state's Republican-controlled legislature without Democratic support, made Walker a lightning rod for protest and prompted a recall election, which he survived.

While Christie's approach would have more appeal to a general electorate, "you have to get nominated first," said Larry Sabato, director of the Center of Politics at the University of Virginia. "Walker is a hero to the GOP base and conservative donors precisely because he didn't compromise, and he was willing to endure a recall election and triumph, on a matter of principle."

Walker is now fighting Burke, a former state commerce secretary, in a nationally watched race to hold on to his job. Michelle Obama campaigned Monday for Burke in Milwaukee.

Polls indicate a "very close" race. Four Marquette University Law School polls since May have placed the race within the margin of error, said Charles Franklin, director of the poll and a professor of law and public policy.

The polls show Walker winning more than 90 percent of Republicans and Burke winning more than 90 percent of Democrats, Franklin said.

Christie - who won reelection last fall with 60 percent of the vote and has touted his victories as a Republican in a blue state - said Monday that the recall had settled divisiveness in Wisconsin over Walker's policies.

"The fact is that the unions tried to recall this governor, and the people of Wisconsin spoke very clearly. They were not divided then," Christie told reporters. Walker won the recall with 53 percent of the vote.

Addressing Walker supporters, Christie said the "big government unions" that "tried to come into this state and take this state over in 2012" want to "make an example of [Walker] to other governors around this country who want to do tough things to put the taxpayers first."

Patrick Murray, a political analyst at Monmouth University, said Walker was "one of the few people who can raise a challenge to Christie as not the only pension-fixing governor in the country."

Walker at one point Monday described Wisconsin's pension system as "the only one in the country fully funded."

New Jersey's pension system is among the worst-funded, a situation predating Christie. While recently downgrading the state's debt, credit rating agencies have cited Christie's decision to reduce state payments into the system in the face of a revenue shortfall.

Any tension between Christie and Walker was unspoken Monday as they toured the Empire Bucket Plant, which makes buckets for construction equipment.

Listening to owner Joe Pertz describe the company's products and point out a recent building addition, the governors paused to share hands with workers, who later lined up to listen to them.

Ervin Holder, who has worked at the plant for more than 30 years, said he liked Christie, though he was more versed in Walker's record "cutting down unions."

"I'm for that," said Holder, who lives in Minnesota. "You get five people sitting there and one person holding the shovel. Give me a break."

Inside the campaign office, tucked in a strip mall, Richard Johnson, 73, of North Hudson, said that the two would make a good ticket as president and vice president. Johnson, a vending machine salesman, said he would pick Walker as president.

"He stood tough with the unions," he said.

Johnson said he was not aware of Christie's record with unions in New Jersey but said he supported the governor. "Some think he's a little too liberal," Johnson said, referring to Christie as "arm-in-arm" with President Obama after Hurricane Sandy.

But Johnson didn't blame Christie, who, at the time, praised Obama. "You know where the money is, so you might as well butter up with it," Johnson said.

Later Monday, Christie traveled to Ohio, where he campaigned for Gov. John Kasich - another Republican seen as a potential 2016 contender.