When the federal government revealed what pot legalization would look like in Canada, it put forward two proposed laws to police the new regime: one to change the rules governing the sale and distribution of the drug itself and another to help police better address impaired driving.

Justice Minister Jody Wilson-Raybould said they were "companion" pieces of legislation.

Now, as legalization creeps closer, it seems the fates of the two bills aren't as closely linked as first thought. The Liberal government's point man on pot said Wednesday recreational cannabis use will become legal even if the impaired driving law is still being debated by the Senate.

"I think both bills are very important but they are not the same bill," said Liberal MP Bill Blair, parliamentary secretary to the ministers of Justice and Health.

"Any delay in Bill C-46 on impaired driving is not an impediment to the passage and implementation of Bill C-45 [the cannabis legalization bill] but we would very sincerely hope that the Senate would be able to deal with both bills in expeditious way."

Blair said that while he believes the new impaired driving legislation will help save lives, police already have the ability to arrest drug-impaired drivers.

"That authority exists. We believe that authority will be enhance by Bill C-46 and that's why we're so hopeful the Senate will deal with it in an expeditious way," he said.

Constitutional concerns

The bill to reform impaired driving laws contains new offences for different levels of drug impairment and gives police the authority to use roadside saliva tests to determine if a driver has drugs in their system.

Perhaps the most contentious part of the bill is the part that deals with alcohol impairment — specifically, the stipulation that police do not need reasonable grounds for suspicion before asking a driver for a breathalyzer test.

Chair and vice-chair of the federal government's task force on cannabis legalization and regulation - Anne McLellan and Mark Ware weigh in on the Senate's concerns about Bill C-45. 8:19

The House of Commons passed the impaired driving law first, sending it over to the Senate. But its progress in the Red Chamber has been slow. The bill was put on the back burner for an intensive, five-committee study of the law that would actually legalize pot, known as the Cannabis Legalization Act. Even before that, some senators pointed to concerns voiced by legal experts that requiring drivers to give mandatory breath samples would be unconstitutional.

The Canadian Bar Association has said the proposed bill "would put the law back to square one, bringing with it a deluge of cases arguing interpretation and constitutionality of the new provisions."

Wilson-Raybould has argued the bill doesn't violate anyone's rights. But it's still not clear when the Senate will be done with that debate.

A move too soon

Conservative health critic Marilyn Gladu told CBC News that it's more important to get both the pot bill and the cannabis legalization bill right than to rush them through Parliament.

The Senate has "a number of concerns and amendments that they would like to bring and so I think the government needs to give those due consideration and at the same time wait until they have clear rules. Otherwise, there will be confusion, I would say, within the police force," Gladu said.

"We expect to see court challenges to C-46 anyway because there is no test for impairment with cannabis, but that said, no rules makes it even less certain."

That sentiment was echoed by Mothers Against Drunk Driving Canada. The advocacy group's legal counsel told CBC News that legalization of cannabis must come with the legal power required to police its use.

"MADD Canada is very concerned about the possibility that Bill C-45 [the cannabis legalization bill] would enacted before Bill C-46 [the impaired driving bill] because Bill C-46 provides traffic safety measures that are needed right now," said Eric Dumschat, legal counsel for MADD Canada.

"Unfortunately, Bill C-46 has been delayed by the Senate for a number of months now but Canada has a drug-impaired driving problem today and has for the last decade at least."

Minister declines to weigh in

Pot legalization, on the other hand, is proceeding on schedule. The Senate has agreed to vote on the bill on June 7, which would still give Parliament a few weeks to deal with any proposed amendments before the summer break.

Officials have said legalization would actually take effect somewhere between eight to 12 weeks after the bill passes, to give provinces and territories time to get their sales and distribution systems up and running.

Just last week, Prime Minister Justin Trudeau said he did not intend to see legalization delayed past summer.

Asked last week about the connection between the two bills, Wilson-Raybould's office declined to say whether the two pieces of legislation were tied.

"It is worth noting that C-46 has been in the Senate for debate since November 1 last year. It should be passed as soon as possible," said a spokesperson.