Taxation and the middle class

[nms]

The Canadian federal debt was relatively low until the late 1970s, then took off around 1984, shrank starting around 1996 and then has increased every year since 2008.  The most recent rise since 2008 is roughly evenly split between the Harper years (2006-2015) and the Trudeau years (2015 to today). Setting aside the unprecedented Covid debt (roughly 2020 to 2022, but there are likely still ongoing Covid costs), what have political parties of any stripe proposed that might actually succeed in lowering the federal debt and/or deficit?  The Conservatives didn't do it, and nor have the Liberals.

What has happened economically in the last 40 years to put the federal government in this position? Will it ever be reversed?