You say this, and yet drilling is at a peak right now. So what companies are not producing or exploring here in favor of elsewhere?The pipeline will create jobs - it doesn't build and monitor itself.
Reducing Middle East imports - Canada already supplies a large amount of its exports to the US; there isn't much room to increase those exports. As for Middle Eastern dependance, a lot of this has to do with policy. Currently, US imports from the Mid-East are at ~21% or so.
THE WTI/Brent differential is a crucial facotr in all of this. When WTI is selling at an almost $20 discount. This differential is not a good thing from the perspective of exploration and production in the US. Companies with global interests, would scale back US operations in favour of exploiting plays that are going to fetch them Brent prices.
Midwest refiners are making higher profits because of the WTI/Brent spread. Their stocks are up. Some savvy hedge funders will probably be able to short the Brent and long sell the WTI as the gap closes. The only losers are some gulf and east coast refineries, but that won't last longer than the spread.
Either way, with the Seaway reversal, and the southern section of XL getting built, I suppose the spread should become a moot point in this topic, long term.
An aside: I bet any people who would support bombing Iran and would also support the pipeline. Since the Iran situation is increasing the spread and the pipeline would reduce it, that's sort of amusing.