When the history of Christy Clark's time as B.C. premier and Liberal Party Leader is written, three critical mistakes will be viewed as precipitating her political undoing.

Ms. Clark stunned the province and many in her own party on Friday when she announced she is quitting not just as Liberal Leader, but also as an MLA. This, after insisting she planned to head a robust opposition against an NDP government operating with a perilous one-seat majority it owes to the conditional support of the BC Greens and their three seats.

She informed her caucus colleagues at a meeting in Penticton of her decision, automatically triggering a leadership election process. Rich Coleman was named interim leader.

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While Ms. Clark had earlier indicated her intention to stay on and fight the good fight, at least in the short term, there were many in her party not thrilled with that plan. And the reason is June's Speech from the Throne, one that was hastily revised to incorporate policies that, in some cases, the Liberals had campaigned against and were shamelessly ripped from the pages of the NDP and Green Party election platforms.

In theory, this was supposed to make it more difficult for the opposition to team up to defeat the Liberals in a confidence vote. Unfortunately, all it did was make Ms. Clark and her government look ridiculous and desperate to cling to office.

The-then premier's credibility was eroded further when Lieutenant-Governor Judith Guichon refused her request to dissolve the legislature and call another election – something Ms. Clark had continually insisted she would not ask for.

But the bigger problem was the Throne Speech. How was Ms. Clark in opposition going to be able to legitimately criticize NDP policies that, in many cases, her government had endorsed in an effort to stay in power?

Perhaps not surprisingly, Ms. Clark's approval ratings cratered immediately after, so did her numbers around questions regarding her authenticity, trustworthiness and likeability.

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Not only that, but the failed strategy also managed to alienate the conservative wing of the Liberal coalition – something that was going to take another leader, with a different vision, to fix.

So the Throne Speech was one costly blunder.

The second was steadfastly refusing to acknowledge widespread criticism that the Liberal government was receiving over the lack of rules regarding political fundraising in the province. It eventually drew international attention, scorn and ridicule. It made the Liberals look like morally corrupt outliers, refusing to change, refusing to stop the cash-for-access fundraising dinners despite the terrible optics they created. Worse, it made them appear arrogant and out of touch.

Even though the New Democrats were playing by the same rules, although not nearly as successfully as the Liberals, they framed the 2017 election as a choice between a party that ruled for the wealthy versus one that promised to govern for the average person. "The rich have had their premier. It's time you had yours." The message resonated deeply with voters. Many in the Liberal Party believe it cost them the election. (Even though they ended up with two more seats than the NDP, it still ended in the defeat of the Liberal government).

Thirdly, the Liberals ran a dull, cautious campaign, refusing to open up the provincial purse strings to offer people something after four years of relative restraint in the name of balancing budgets. Even Ms. Clark would later acknowledge this was a mistake.

In the end, the combination of these tactical miscalculations, as well as others, led to the unlikely sequence of events that resulted in Friday's startling announcement out of Penticton. Four months ago, the thought that Ms. Clark would be gone from politics by the end of summer was unimaginable. Now it will be a reality.

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What will her legacy be? Well, she will be remembered for her steady fiscal stewardship, the strongest such performance in recent B.C. history. Five balanced budgets is not easy to pull off, although some will say she did it by raiding the profits of Crown corporations such as ICBC. (Also, the overall debt grew significantly on her watch). Ms. Clark's other great achievement was winning the 2013 election, something she was not supposed to do. And she did it almost singlehandedly.

But she also did it on the promise of LNG riches that never materialized. Petronas's decision this week to end its plans to open up a plant in B.C. represented another huge blow to Ms. Clark's LNG utopia. There will be no debt-free B.C. or $100-billion prosperity fund – there never was going to be.

Christy Clark has been a polarizing political figure. But she also engendered tremendous loyalty inside her party. She will be remembered as a tough, scrappy fighter, who was often too politically calculating.

She will go down as the sixth-longest serving premier in the province, the first female premier in the country to be elected in two successive elections. Her exit from politics was messy and unseemly, however, and sullied her legacy unnecessarily.