Harper's plans for the Senate will create a showdown against the provinces.

Senate showdown looms - thestar.com
On one side, there will be the Conservative government. On the other side will be the opposition parties (or, at least the NDP) and the provinces - many of which would like to abolish the Senate altogether (as the NDP would like to do).

Excerpts:
Ontario is poised to join Quebec in a constitutional showdown with
Prime Minister Stephen Harper and his plans for Senate reform.

Quebec has already served notice
that it is preparing to challenge Harper’s go-it-alone approach to
changing the Senate — arguing that he can’t change a basic institution
of Parliament without the support of the provinces.

...

Such a battle would pit Harper’s majority government against Canada’s
two largest provinces and threaten to open up the kind of
constitutional quagmire that swallowed up the last Conservative majority
government in Canada in the 1980s and early 1990s.

It also could be a sign of a new frontier opening up in opposition to Harper’s Conservatives.

Harper’s main headaches were caused
by his federal political rivals when he had minority control in Ottawa
from 2006 to the recent election. But with a majority in Parliament,
easily able to pass his legislation, Harper may be forced to look
increasingly to the provinces for potential obstacles to his plans.

Interim Liberal leader Bob Rae, a
former Ontario premier, agrees that Harper is out on a constitutional
limb in trying to change the Senate without provincial consent.

“Look, the Senate is a child of the
Constitution of Canada. It doesn’t belong to Stephen Harper,” Rae said.
“It’s all nonsensical. The Senate, if there’s going to be reform, it has
to start with the provinces and the federal government sitting down and
trying to get to an answer. And that’s the beginning and the end of
it.”

Constitutional expert Ned Franks also calls the new legislation “dead in the water.”

“That one is sure to get shot down by
the Supreme Court because that’s a substantial reform and that can’t be
done without the consent of the provinces,” Franks told the Star’s Richard J. Brennan this week.

Ontario is now officially in favour
of abolishing the Senate — a position also championed by the NDP
opposition in Parliament, as well as several provinces such as Manitoba
and Nova Scotia.

“If the government is going to insist
on reforming the Senate, we think it should be abolished,” Smith said,
echoing Premier Dalton McGuinty’s recent declarations on that same
score.

...

NDP leader Jack Layton said Tuesday that the proposed reforms just
reinforce his party’s view that the Senate should be abolished. Just
before the last election, the NDP introduced a bill to hold a nationwide
referendum on scrapping the Senate.

“They are going to create a monster
here, because you will have at the end of the day … an elected body that
may or may not be elected, that the Prime Minister may or may not
accept the recommendations that come out of an election,” Layton said.
“It’s going to be one ugly scene and throughout that generation, we will
spend $100 million a year feeding this beast which will by and large
stand in the way of democracy in this country … It’s a disaster for
Canadian democracy, all wrapped up in the guise of Senate reform.”