NASHVILLE (AP) — Partisan divisions over immigration, education and health care are intensifying as dozens of the nation's governors meet just months before elections thick with presidential implications.

The three-day gathering of the National Governors Association represents the group's final meeting before many state leaders face voters in an election season that will decide the balance of power in statehouses from Nevada to New Hampshire and could end some presidential campaigns before they begin.

New Jersey Gov. Chris Christie and Wisconsin Gov. Scott Walker, a first-term governor locked in a heated re-election battle, lead a group of ambitious Republicans set to appear at the downtown Nashville conference opening Friday. Maryland Gov. Martin O'Malley is among the Democrats weighing a 2016 presidential run.

"You can be in a room where you have six, seven, eight people who are thinking they might run for president in two years, which makes for some interesting personal dynamics at times," Tennessee's Republican Gov. Bill Haslam said.

Another potential presidential contender, Vice President Joe Biden, addresses the conference on Friday. He is expected to focus on the need to strengthen the nation's infrastructure and workforce development, avoiding overtly political topics in a semiannual conference that generally strikes a bipartisan tone. But with midterm elections ahead, politics looms over the entire event.

Biden is set to headline a fundraiser to benefit Democrats' midterm efforts before his afternoon speech, while Christie and other Republican leaders will do the same for their side.

The vice president's appearance comes as the Obama administration faces criticism about its handling of an influx of Central American children sneaking into the country to escape their violent homelands. The issue has reignited a fierce debate over immigration reform, which has stalled in a gridlocked Congress despite overwhelming support from the White House, the business community, faith leaders and many establishment Republicans.

The administration's most outspoken Republican critics — Texas Gov. Rick Perry, among them — are not attending the conference. But other governors of both parties who have so far avoided the explosive issue are likely to weigh in.

Other topics will likely include education reform and Common Core education standards, which were largely supported by governors of both parties before becoming a popular target of tea party activists.

Social issues may come up as well. The meeting is the NGA's first since the Supreme Court ruled that some employers with religious objections could refuse to cover women's birth control as required under the federal health care law. The ruling injected women's health and religious freedom into the midterm elections, issues that Democrats and Republicans are trying to use to their advantage.

While Democrats are expected to struggle in congressional elections this fall, they are optimistic about their chances in the nation's 36 races for governor set for November.

The GOP is defending 22 seats compared with Democrats' 14. The Republicans include several governors who could seek the presidency in 2016 so long as they survive re-election tests, among them Walker, Ohio Gov. John Kasich and Michigan Gov. Rick Snyder.

"I don't believe that the former governor of Wisconsin is an effective presidential platform from which to run," Danny Kanner, a spokesman for the Democratic Governors Association, said in predicting Walker's defeat this fall. "We are on offense in governors' races."

But it won't be all work this weekend. Events on the schedule include a reception at the Country Music Hall of Fame, the iconic Ryman Auditorium, the governor's mansion and a picnic at the Hermitage, President Andrew Jackson's home. Musical acts will include Vince Gill, Amy Grant and Trace Adkins.

"We've been working hard to show them a little taste of Tennessee," Haslam said.