OTTAWA, June 22 (Reuters) - Canada's Liberal government avoided a battle over its budget bill on Thursday as the Senate backed down over proposed changes, but standoffs with the unelected upper house may become the new normal.
Senators agreed to pass the budget without amendments, despite disputes over several parts of the legislation, after Prime Minister Justin Trudeau and his finance minister said the government would not accept changes.
While the Senate has had periods when it took a more activist approach, it has been decades since the body forced a showdown with the House of Commons, whose elected members include Trudeau, his cabinet ministers and opposition leaders.
The Senate became a major irritant to Trudeau in the past few weeks, offering amendments to high-profile bills on assisted dying, terrorism, the budget and other issues, at a time when he hoped to head into the parliament's summer recess on a high note to counter a refreshed Conservative opposition.
"What you've seen in the last year is sort of a natural evolution. The Senate is playing more of an activist role," said Senator Andre Pratte, an independent who pushed for changes to the budget bill.
Trudeau himself may be partly responsible for the Senate's sudden independence. In 2014, while in opposition, Trudeau expelled all 32 Liberal senators from the party's caucus amid a Senate expenses scandal in a bid to curb partisanship. They remained members of the Senate but are no longer subject to party discipline.
Since taking office in 2015, Trudeau has appointed a range of non-partisan community leaders to the upper house, giving him less leverage to pressure them to support his agenda.
"More senators are now independent of political parties, so we feel freer to suggest amendments than in the past," said Pratte, who was appointed by Trudeau in 2015.
Few senators are prominent public figures, except a few former hockey players and journalists or those made infamous through scandals.
While the new independents have been largely loyal to Trudeau, his old Liberal colleagues are less predictable.
"There is a strong sense in which the Senate Liberals are holding onto a bit of a grievance from ... (when) Trudeau kicked them out of caucus," said Emmett Macfarlane, a University of Waterloo political scientist who advised Trudeau on the Senate reform.
But he said the prime minister need not fear the Senate given its lack of public support. Nearly a third of Canadians believe the Senate should be abolished, according to an April Angus Reid poll, but attempts to do so have proven constitutionally difficult.
"It is the Senate that needs to tread a little carefully here," Macfarlane said. "If it becomes obstructionist, it does that at its own peril, because it doesn't have the political capital to spend on a big fight with the House of Commons."
The prime minister's office declined to say whether it expected more battles when parliament resumes in the fall. Spokeswoman Andree-Lyne Halle said the office hoped to "continue to work productively with the Senate" to pass legislation.
But Campbell Sharman, a political science professor at the University of British Columbia, said he hopes the genie is out of the bottle and the Senate independence will continue.
"We are in this kind of transitory interesting phase," Sharman said. "Of course the government hates it - they always hate strong upper houses." (Reporting by Andrea Hopkins; Editing by Leslie Adler)