HALIFAX -- There was a time when David MacLeod could have been a shoo-in candidate for the federal Conservative party.

The former military man was a card-carrying Tory whose 27 years of service in the Canadian Forces would have been a strong political asset in the rural Nova Scotia riding where he grew up.

But late last month the plain-spoken veterans rights advocate was elected to become the Liberal candidate in Central Nova, the Conservative stronghold where he will take on Justice Minister Peter MacKay in the next federal election, scheduled for October 2015.

MacLeod, 49, says his political transformation started around 2006, soon after Conservative Prime Minister Stephen Harper was first elected to govern with a minority.

"As the party started moving farther and farther right, I started to get more worried as time went on," he said in a recent telephone interview from his home in Antigonish.

"Ever since 2006, it seems like there's been this continuous pressure ... to cut benefits for veterans. Why? For the most part, veterans will not speak up."

MacLeod says his disenchantment with the Tories grew as he studied the veterans charter, which the federal government has pledged to change after years of protests from veterans groups.

Suffering from chronic pain caused by a gunshot wound he received during a training accident in the 1990s, MacLeod was medically released from the military in February 2010.

He got involved in a advocacy group for disabled soldiers and later attracted national attention when he and another vet, Jim Lowther, made a presentation about homeless veterans to a parliamentary committee in Halifax in February 2012.

During the meeting, Conservative MP Rob Anders appeared to fall asleep, prompting subsequent complaints from Lowther and MacLeod. Anders responded by saying the two veterans were "NDP hacks" and supporters of Russian President Vladimir Putin.

Anders later apologized for his remarks and was removed from the committee within weeks.

"I was shocked that a member of Parliament would have the audacity to accuse us of being disloyal to Canada," says MacLeod. "I was so brutally insulted."

Still, the ugly incident did not push MacLeod to join the Liberal fold. He was still a member of the Nova Scotia's Progressive Conservatives at the time.

He says the tipping point came last May when Veterans Affairs Minister Julian Fantino came under fire for walking away from Jenifer Migneault, whose husband is a veteran with post-traumatic stress disorder.

Opposition critics demanded an apology after Fantino emerged from a meeting and failed to stop after Migneault hollered several times as she followed him down a corridor.

"She was trying to get him to understand the challenges that spouses go through when they're taking care of someone with PTSD," MacLeod says. "That was infuriating. ... It had become increasingly clear that the government was becoming hostile toward veterans."

As for his looming battle with MacKay, MacLeod says he's not intimidated by squaring off with a senior cabinet minister.

"I don't fear Peter," he says. "I've seen the results of his work, and I'm not impressed."

MacLeod then switches to campaign mode, quickly pointing out that the unemployment rate in his area was around 15 per cent and that MacKay faces challenges dealing with festering environmental issues at the local pulp mill.

"There's been no real improvement since I left," says MacLeod, who grew up in New Glasgow. "The whole place has stagnated."

MacKay declined a request for an interview. He issued an emailed statement about MacLeod's candidacy saying: "I commend him for his service to Canada. We welcome everyone to the democratic process."

Still, the political rookie faces a huge challenge in Central Nova, which MacKay won by more than 12,000 votes in the 2011 election.

MacKay has held the riding -- redrawn in 2004 -- since 1997. His father Elmer held the seat from 1971 until 1993, except in 1983-84 when he stepped aside to let Brian Mulroney contest the seat in a byelection.