Oh just stop with the blood for oil bullshit. If invading a country was all about America's need for oil you would have invaded us.
Hell's bells you won't even build a pipeline for oil.
"Canada reigns as the United States' leading oil supplier, exporting some 707,316,000 barrels of oil per year (1,938,000 barrels per day) — a whopping 99 percent of its annual oil exports, according to the EIA."
United States Oil Imports OPEC GlobalPost
Oh come on. This isn't the simple argument you're trying to make out.
Let's try and be a little bit more intelligent shall we?
In 2001 there were 4 OPEC countries that really didn't like the US.
Venezuela, Iraq, Iran and Libya.
Venezuela's turn was first. A coup d'etat was supported by the US with quite a bit of money, and help.
Why Venezuela first? Well Chavez was trying to use OPEC as an anti-American tool, reducing the amount of oil and pushing up world oil prices.
Then it was the turn of Iraq. Invaded in 2003.
Then it was Libya in 2011. If you ever go back and read what McCain said during this time you'd realise the right pushed this one for all it was worth.
Then there's Iran, sanctions, supposedly over their nuclear weapons, but it's all about oil.
On your ridiculous point of the US invading Canada. The US doesn't need to invade Canada. This isn't about getting free oil. It's about reducing the world oil price.
OPEC have, by my estimates, about 1,200,000 million barrels. This is compared to all non-OPEC countries in the world who have, perhaps 500,000 million barrels. You see why OPEC is so important? You see why the US doesn't want to allow OPEC to dictate oil prices?
The US has Saudi Arabia on its side, it doesn't need to invade them. The Saudis won't do anything to harm the relationship. If OPEC reduce production, the Saudis might go along saying it's OPEC. They won't, however, do it off their own bat.