Senate Majority Leader Mitch McConnell (R-KY) pledged that one of the first measures the new GOP-dominated Senate would take up would be a bill approving the construction of the Keystone XL Pipeline. Given that the vote to approve of the pipeline fell only one vote short of passage in the lame duck session of the last, Democrat-dominated Senate, it is reasonable to expect that the six Democratic votes that Republicans need to secure passage of the bill can be mustered.

Even if the measure does pass, however, CNN reports that President Barack Obama is likely to veto it.

CNN Chief Political Analyst Gloria Borger reported on Tuesday that, according to Sen. Jeanne Shaheen (D-NH), the president suggested strongly that he would veto any measure approving of that transcontinental pipeline’s construction. Following CNN’s reporting, the president issued a formal veto threat.

While Obama has been far away from the continental United States for much of the last month, he has experienced a remarkable bump in his job approval rating. As The Washington Post’s Aaron Blake observed in November, an Obama veto of the popular Keystone Pipeline is only likely to remind the public why they were sour on him to begin with.

Poll after poll has shown support for Keystone is somewhere between very strong and overwhelming. A Pew Research Center survey this month showed support for the project at nearly two-to-one, 59 percent to 31 percent. And that was about the lowest level of support we’ve seen to date. Support has registered as high as two-thirds of Americans.

And as another recent Pew poll showed, it’s not just Republicans and independents driving support for the project. In fact, basically the only group that opposes it is the most liberal of Democrats.

According to Pew’s breakdown from June, three of the four Democratic-leaning groups — including religious Democrats, young Democrats and the most moderate Democratic leaners — all supported the project two-to-one.

Which is a long way of saying that Obama would likely have very few supporters were he to wield his veto pen, as the White House suggests he will following votes by the House and Senate — which by all indications will approve the bill.

But as Blake also observed, Pew found that a majority of only one subgroup disapproves of the construction of the pipeline: “Solid liberals.”

Given this condition, Obama’s decision to veto this project makes perfect sense. With the president’s legacy in the form of the Affordable Care Act not only deeply unpopular but the subject of regular repeal efforts, Obama is scrambling to live up to his promise as a transformative liberal president. This is why he pursued unilateral immigration reform; this is why he’s seeking normalized relations with Cuba; this is why he will veto Keystone. It’s not about sound policy or the good of the nation. It’s about exhibits in the Obama presidential library.

So, the question now becomes can the Republicans in the House and Senate drum up the Democratic votes necessary to override a presidential veto? While it is not impossible, that is a particularly tall order. The most likely outcome in the event of the passage of Keystone will be that the bill fails after a veto.

The press, if they were so inclined, might call Obama’s decision to thwart a popular initiative endorsed by the people’s representatives “obstructionism.” But then they would be making a Democratic president play by the rules they have set only for Republicans, and we cannot have that.