Why does "gate" mean scandal?

Here's an amusing take on governmental incompetency from David Wilkins, the US ambassador to our great country. He thinks that a leaked memo from our government detailing how Barack Obama is talking out both sides of his mouth about NAFTA cancellation is tantamount to Canadian interference in US elections. To Ohio voters, who are losing jobs under the current NAFTA agreements, he's saying that he'll scrap NAFTA. But his economic adviser, Austan Goolsbee told the Canadian Consul General Georges Rioux that no such plans were in place.

I'd like to ask a couple questions at this point:

1. Since when does the US care about anything Canada does or says? Thinking that we have influence and pressure to bring to bear in the US election is more than a little far-fetched. In fact, it would likely be the other way around - "I'm votin' Bush, 'cuz those Canadians hate that guy." Frankly, we don't care who wins the election now that Bush is out.

2. Why would we be supporting NAFTA anyways? Despite numerous decisions by NAFTA governing bodies that softwood lumber tariffs are unfair, they remain unchanged. We've never profited under NAFTA, even when we've won decisions. Go ahead and scrap NAFTA! Let's get a real regulatory body in place or scrap the thing altogether. The US would be foolish of course, as the original NAFTA was drawn up under the shadow of overwhelming US economic power. See what the new agreements look like now that some pundits are predicting economic collapse.

3. Who is surprised about politicians lying straight to our faces like that?

4. What does it even matter when the next president is going to be John McCain anyways?

5. Since when do the Americans need our help in election interference, and why would we do it for free when Diebold gets paid for it?