Justin Trudeau’s latest campaign promise pretty much describes the typical Liberal campaign promise: it sounds good, but it’s also too vague to be taken seriously.

Liberal Leader Justin Trudeau is promising to reform Senate appointments and introduce an “open, non-partisan, merit-based process.”

“As [Liberal Party] leader, I took decisive action removing Liberal senators from my caucus because partisanship and patronage need to be removed from the Senate,” Trudeau told supporters at the official opening of his campaign office in the Papineau riding of Montreal Tuesday.

Of course it should be said that Mr. Trudeau’s record on “open process” is — well, “superficial” is probably the kindest word. “Non-partisan” presumably means he won’t be appointing people with Liberal Party memberships, but that’s still torquable, based on the following question: if Bob Rae didn’t renew his Liberal membership and gets appointed to the Senate, is he considered “non-partisan”?

But it’s the phrase “merit-based” that really takes the cake. Because in order for it to be credible, Mr. Trudeau would have to explain exactly what merits a person has in order to be considered for the Senate. And that can create all sorts of mischief.

Of course there are some rules about who can be appointed. According to the Senate’s own web page, a prospective senator must:

• be a Canadian citizen
• be at least 30 years of age
• own $4,000 of equity in land in the home province or territory
• have a personal net worth of at least $4,000
• live in the home province or territory

One of the reasons why Mike Duffy is in such trouble is that he claimed a summer residence, in Prince Edward Island, as his actual home, while investigators pointed out that he didn’t actually live there anywhere near long enough for anyone with a dictionary to agree with him.

Apart from that, the only Canadians really excluded from consideration are young people who rent their homes and don’t have cars, because they haven’t really accumulated enough net worth. So that doesn’t really help when we consider merit.

But how about this bit from the Senate page?

Increasingly, the Senate reflects our multicultural society. Senators come from many different ethnic backgrounds and religions. Canada’s First Nations and Black communities are represented in the Senate, as are Canadians of Arab, Asian, Italian, Jewish, Ukrainian and other origins.

So: is racial background, or religious belief, part of the definition of “merit” that Mr. Trudeau wants to use? If the behavior of Patrick Brazeau is anything to go by, probably not.

Of course, we do expect our senators to behave ethically while they hold their seats. But was there anything in Mike Duffy’s background and history as a journalist to show he would be profligate in his spending? Or Pamela Wallin’s? Mr. Trudeau might be tempted to say that anyone who works or has worked for CTV News would automatically be disqualified for Senate consideration, but would people consider that a fair condition?

Then we have to consider “merit” in terms of what we expect the Senate to actually do. If we say “pass good legislation” and “stop bad legislation” — well, that’s only going to bring up the issue of partisanship, but at a stage further down the process.

So it’s simple. If Mr. Trudeau wants to make Senate reform a campaign issue, he’s going to have to do more than say something that sounds good. He’s going to have to debate his competition in detail — and that will be a harder game than he or his handlers seem to be expecting.