It's been a busy "off-week" on Parliament Hill. First Eve Adams bolted from the Conservatives — after the party abandoned her — to become a Liberal.

As floor-crossings go, this was a doozy. Twitter erupted. Talking heads talked. Ink was spilled. And people outside of Ottawa wondered why any of it mattered.

Then German Chancellor Angela Merkel dropped by to update Stephen Harper on the difficult negotiations to broker some kind of peace in Ukraine. The prime minister is a staunch supporter of Ukraine, as well as a vocal and consistent critic of Russian President Vladimir Putin's interference there.

Sandwiched between those two events, a cabinet shuffle dismissed as minor in scale — but of significance to the Conservative agenda — as the prime minister plugged the gaping hole created by the abrupt departure of former foreign affairs minister John Baird for the greener pastures, if only in terms of earning potential, of the private sector.

When it comes to filling cabinet seats, subtraction always leads to addition. Lose one minister. Move three. And that's what happened here.

Rob Nicholson moved from defence to foreign affairs. Jason Kenney moved from employment and social development to defence. Replacing Kenney is Pierre Poilievre, who keeps his existing duties as minister responsible for democratic reform.

Three moves. A vacancy filled. Just another problem of political calculus answered. And the media, for the most part, moved on.

So why does it merit a deeper look? Because these three men will play critical roles advancing the foundation issues of the Conservative re-election campaign this year: Jobs and the economy, public safety and combating terrorism.

The new messengers

In shifting Nicholson laterally, Harper ensured continuity in Canada's representation on certain key international files. As defence minister for the past two years, he is familiar with Canada's commitments to the battle against ISIS in Iraq as well as the efforts now being led by Germany and France to broker a ceasefire in Ukraine.

Nicholson also fits nicely into the role of number two, behind the prime minister, on these files.

He rarely speaks publicly, and even more rarely strays from the government's official talking points. Reporters hate that. So do opposition MPs.

Job switch. With the resignation of John Baird, left, Rob Nicholson moves over from defence to become the new foreign minister. (Reuters)

But for a government that demands consistency in its messaging, it's a trait so highly valued by Harper that Nicholson's inability to speak Canada's other official language wasn't a deal breaker.

The bilingual Kenney, on the other hand, remains one of Harper's most effective communicators. As employment minister he negotiated, wheedled and cajoled the provinces into an agreement on the Canada Job Grant — the controversial skills training program that originally would have seen Ottawa’s share of the cost clawed back from money given to the provinces for other kinds of job training.

Kenney will be the lead as the government decides whether to extend Canada's commitment to the bombing campaign in Iraq, and to expand the training role now played by a few dozen Canadian soldiers — a role that has already evolved from working with Kurdish fighters behind the lines, to accompanying them into the fighting.

He will now become one of the government's lead voices on the terror file.

Jobs, jobs, jobs

And then there's Poilievre, the last name on the release announcing the cabinet changes, but the one who arguably faces the biggest challenge.

He inherits the jobs portfolio at a time when the energy sector is shedding workers, and retailers such as Target and Mexx closed their Canadian stores, laying off thousands.

Stephen Harper's new election faces: Employment Minister Pierre Poilievre (left) will carry the can on jobs; Defence Minister Jason Kenny will battle ISIS. (Reuters)

He inherits the still unresolved controversy over the Temporary Foreign Workers program, which was being abused by many employers who imported non-Canadians to fill jobs that should go to Canadians, as CBC reported.

Now, some provinces are lining up for a fresh battle with Ottawa over job training. Ontario wants the surplus in the Employment Insurance fund to pay for new training programs.

Saskatchewan wants the government to address an inequity in the EI program that sees the province pay more into it than it receives in benefits.

Negotiating, compromising. These aren't skills generally seen in Poilievre who, despite being only 35, has already spent a decade in Parliament.

The new employment minister is better known for his combativeness, for being the guy Harper turned to when he wanted to stonewall the opposition over allegations of election chicanery, and for being the one to bash through changes in the election law despite determined opposition from across the floor, from Elections Canada and nearly every election expert in the country.

But Poilievre is also a stickler for detail, known to correct reporters for the smallest errors in their coverage of the Election Act changes. He knows his files. Conservatives insist it's those skills, not the partisan combatant, that won him the promotion to the difficult employment brief.

Along with Finance Minister Joe Oliver, Poilievre will serve as one of the government's point men on the economy heading into the election.

He will be a key minister defending the Conservatives' financial stewardship through this current bumpy period.

It's the issue on which the Conservatives would most like to be judged.

With the recent plunge in oil prices prompting economists to lower Canada's growth projections and forcing a delay in tabling the federal budget, they will almost certainly get their wish.