CONCORD, N.H. -- Former Florida Gov. Jeb Bush is laying the groundwork Friday for an all-but-certain 2016 presidential campaign with a visit to New Hampshire, a key election state that gave his father and brother problems during their own paths to the White House.

Bush has lately received the most attention among potential Republican presidential candidates, but the race for the party's nomination remains wide open. That is part of the reason Bush -- and others -- are heading to New Hampshire even before they are official candidates. The northeastern state hosts the first primary election in the state-by-state nomination process.

"It's as wide open as it's ever been," said Fergus Cullen, a former state Republican chairman who is slated to host Bush at his home on Friday evening. "I don't think anyone has the kind of advantage that would let anyone be called a front-runner."

The situation for the Republicans stands in contrast to the Democratic side, where Hillary Rodham Clinton remains the clear favourite for the nomination despite a recent controversy over her email practices when she was secretary of state.

Bush plans private meetings this weekend with party leaders and two public sessions with voters in New Hampshire. The state plays prominently in his plans to win the nomination, but it has a complicated history with his father, former President George H.W. Bush, and his brother, former President George W. Bush.

George H.W. Bush lost the New Hampshire primary to Ronald Reagan in 1980. Eight years later, he carried the state in both the primary and the general election to win the presidency. But he went on to lose the state in his unsuccessful 1992 re-election bid against Bill Clinton.

His son, George W. Bush, lost the New Hampshire primary to John McCain in 2000, though he ultimately won the nomination and the presidency. He also lost the state in the 2004 general election to Democrat John Kerry but carried enough other states to win re-election.

"They've always been respected and a family that is thought to be close to New Hampshire," said former New Hampshire Gov. John H. Sununu, who served as George H.W. Bush's White House chief of staff.

That doesn't mean Sununu is a guaranteed backer of Jeb Bush. "It is so early in the process," he said. "No one has started paying attention yet."

Jeb Bush goes to New Hampshire Friday anticipating serious questions about his candidacy among conservatives. For instance, he has angered conservative tea party activists with his backing of an immigration overhaul proposal.