What's stopping us from simply pausing crude oil and electricity exports to the US?

The US relies heavily on imported oil, to the tune of 8.5m barrels per day. Canada supplies 4m of those barrels.

The US Strategic Petroleum Reserve is at record lows, at 395m barrels. Many US states (like New York) rely on Canadian electricity.

Assuming that nobody else makes up that shortfall, that gives Trump around 88 days to build a logistics network to fill in the remaining 4.5m barrels per day. It's safe to say that actual work (like logistics and planning) isn't his strong suit.

Given the interconnectedness of their fuel supply (Canadian crude crossing the border to be refined, and refined product also coming north), I'm pretty sure the US market would react very negatively to an immediate shutoff of fuel supply, with prices at the pump jumping significantly and quickly.

If Trump ran on a "cheap gas and eggs" platform and then immediately pivoted to a "let's start a trade war with our closest allies for no reason" administration, I'm pretty sure his voter base would respond negatively to the cost of gas doubling overnight.

Trump even said that the US doesn't need Canadian oil or electricity - why not prove that point for him? What's to stop our federal government from stopping the flow of oil and electricity immediately?

If the reason is an expected US military invasion, why not do it now while it's clear that Canada has done nothing to warrant an invasion - before we have to retaliate further, and Trump can put together an actual casus belli?