When Harper took power in 2006, he was left with a fantastic $13.8 billion surplus from the Liberal government under Paul Martin. In 4 years he spent us into a record $55.6 billion deficit, but was able to climb out of it again in another 5 years by cutting social programs drastically and by affording tax breaks to the Canadian public that had a much lower impact than advertised. He managed to climb to the current surplus of over $1 billion.
Edit: oops, they lied. The conservative government under Harper actually left us a deficit of $1-billion but cooked the books a month before election time.
Deficit spending isn't necessarily bad - after all, most of us are used to the idea of taking on a mortgage to afford a home - but 55.6 billion dollars was an incredibly risky move that could have spelled disaster for us.
The idea that the Liberals under Trudeau can't possibly run a deficit for three years and balance the budget in year four is absurd.