Paul Martin welcomes Belinda Stronach into the Liberal party in Ottawa, Tuesday. (CP photo)

Belinda Stronach, who ran for the leadership of the Conservative party in early 2004, has crossed the floor to the Liberal party and will sit in Paul Martin's cabinet.

The millionaire businesswoman becomes minister of human resources and skills development, the prime minister said Tuesday morning. She will also help the Liberals implement the recommendations in the Gomery report on the scandal-plagued sponsorship program when it is delivered later this year.

Stronach's defection could keep Martin's minority government in power as it faces two key votes on its 2005 budget Thursday. Hours after her announcement, the Tories changed direction and said they would support the budget but still try to bring down the government on an amendment.

"After difficult reflection, I reached a conclusion," Stronach told reporters in Ottawa. "I cannot exaggerate how hard this was for me, but the political crisis affecting Canada is too risky and dangerous for blind partisanship."

She also said Conservative Leader Stephen Harper is not sensitive to the needs of all parts of the country, and is jeopardizing national unity by allying himself with the Bloc Québécois.

"The country must come first," she said.

Stronach said that someday, the Conservatives will grow and strengthen to become a worthy challenger to the Liberals. In the meantime, she thinks her place is with a party that is more responsive to the needs of cities, women and young people.

She also said she is looking forward to tackling the Gomery recommendations when they are presented.

"Only when the people of Canada have renewed confidence and faith in the systems of government can we return to economic prosperity."

Small-l liberal in Conservative ranks

Stronach, 39, is a small-l liberal who has not always been comfortable within the Conservative ranks, especially on the issue of same-sex marriage.

Last week, she said it would be unfortunate if the Liberal government fell before the 2005 budget was passed because it contained measures on municipal funding that were of great importance to her constituents in the Toronto-area riding of Newmarket-Aurora.

The former president and CEO of auto parts maker Magna International Inc. lost the Conservative leadership race to Harper in March 2004.

Stronach's father, Magna founder Frank Stronach, ran unsuccessfully for the federal Liberals in 1988 when John Turner was leader of the party.

Stronach said she broached the matter with former Ontario premier David Peterson, who is a family friend, after running into him and his wife at an event in Toronto last week.

Peterson, a Liberal who led a minority government in Ontario in the 1980s before winning his first majority, spoke to her at some length before arranging conversations with federal Liberals and eventually the prime minister.

'I can count,' Martin says of budget vote

The alliance with Stronach could keep Martin's minority government alive in two key budget votes expected Thursday.

Her defection from the Conservatives gives the Liberal-NDP coalition on the budget a total of 151 votes, not including Speaker Peter Milliken, a Liberal MP who votes only in the case of a tie.

The Conservatives and Bloc, who had threatened to oppose the budget, hold a combined total of 152 votes.

There are three Independent MPs, one of whom, Carolyn Parrish, has said she will vote with the Liberals. The other two, Chuck Cadman and David Kilgour, have not said which way they will vote.

"We still don't know whether the budget will pass or not, [but] I've got to tell you, I can count," a visibly pleased Martin said before the Tories announced that they would support the budget vote.

Martin called Stronach a "gutsy" new part of his team.

In the June 2004 election, Stronach beat Liberal Martha Hall-Findlay in her riding by 689 votes.

Martin said Hall-Findlay, who has already earned the Liberal nomination for Newmarket-Aurora for the next election, has agreed to step aside in favour of Stronach's candidacy.

Intergovernmental Affairs Minister Lucienne Robillard had been leading the Department of Human Resources and Skills Development since mid-January, when cabinet was shuffled.

Robillard will now be intergovernmental affairs minister only.

Pressed on how her decision will affect her romantic relationship with Central Nova MP Peter MacKay, the deputy leader of the Conservatives, Stronach called that a "personal matter" that she did not intend to comment upon.

She also said she had the "greatest respect" for MacKay.

In an interview with CBC Newsworld, Stronach repeated that she was uncomfortable with lining up with the Bloc to bring down the government.

When asked why she had earlier voted with her party and the Bloc on a motion calling on the government to resign, she characterized the vote as only "procedural."