When the Conservatives tabled a motion asking the House of Commons to "take note" of the memorandum of understanding signed between the federal and Alberta governments and express its support for the construction of a pipeline, the Official Opposition presumably hoped, one way or another, to make trouble for the Liberal government.
According to the logic of these things, the Liberals only had two bad options.
If Mark Carney and his cabinet decided to vote in support of the motion, they no doubt risked highlighting dissent about a pipeline among Liberal backbenchers. At the very least, it is hard to imagine how Steven Guilbeault could have supported the Conservative motion.
But if Carney and the Liberals decided to vote against the motion, the Conservatives would surely hold that out a

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