(CNN) Maine Sen. Susan Collins has built a reputation as a maverick. She burnished those credentials by being one of three Republicans to vote against the Republican health care plan (that sought to replace Obamacare) in 2017.

Democrats are hoping Collins will defy her party once again and vote against President Donald Trump's Supreme Court nominee Brett Kavanaugh. With Sen. John McCain seemingly on the sideline, one Republican "no" vote could sink Trump's Supreme Court nominee.

But a Collins "no" vote on Trump's nominee is not something Democrats should bet on. She's never voted against a Supreme Court nominee of either party. Further, Collins is a Republican, and the person nominating Kavanaugh is a Republican. That's normally a recipe for a vote for confirmation to the Supreme Court.

Even worse for Democrats' hopes, Collins was a more reliable vote for her party last year than in any other year she's been a senator.

Back in 2017, I wrote a piece about how Collins was the "Real Republican Maverick". According to Congressional Quarterly, Collins had voted with her party on party-line votes (ones in which at least half the Democrats voted one way and half the Republicans voted another) just 59% of the time between 1997 and 2016. The average senator during that stretch had voted with their party about 90% of the time.

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