Given the opportunity to write the history of his presidency -- an opportunity he will soon be afforded, much to his bank account's benefit -- President Obama will almost certainly highlight three things.

First, of course, the fact the the Affordable Care Act provided health insurance to millions more Americans (with the percent of the country that lacks insurance just hitting a low of 9 percent.) Second, his efforts to repair relations with Iran and Cuba, on which the jury is out. And third, that Barack Obama was the first American president to get serious about climate change.

To that end, Obama on Friday finally, after a process that began late in the second term of George W. Bush, rejected approval for the Keystone XL pipeline to cross the border into the United States. TransCanada, the company that hoped to build the pipeline, clearly saw the writing on the wall when it tried earlier this month to rescind its application in the hopes that the next president might be more receptive. The Obama administration was not fooled by the attempt.

The rejection of the pipeline is, by now, entirely symbolic. While estimates of the number of long-term jobs created by the project varied depending on the point being made by the person doing the counting, the State Department figured that about 50 people would get long-term work from it. Over the short-term, during the two years it was being built, the number would be over 40,000. The pipeline wouldn't have lowered fuel prices, either, in large part because such prices are heavily dependent on international markets.

As MSNBC's Benjy Sarlin noted on Twitter, choosing to announce the rejection right after robust employment numbers were reported Friday morning, and while gas prices are low, makes political objections on those issues less relevant anyway. Obama was not hesitant in pointing these facts out during his announcement.

There was economic damage done by the process of rejecting the pipeline -- in Canada. Much of that damage has already had an effect, as the oil producers in Alberta that were relying on the pipeline to get their product to a coast (in this case, the Gulf Coast) have been hammered by a glut of oil that they can't move, which comes on top of the global drop in prices. Investors have been skittish about long-term prospects, as was reported last month. (The new prime minister of Canada "expressed his disappointment" when he and President Obama spoke about the decision, according to Obama on Friday.)

Obama lamented the "overinflated role in our political discourse" the pipeline played when he announced that he was deciding against its approval (or, more accurately, that he agreed with the rejection driven by the State Department, which was the actual decision-making organization). That role is directly the result of activism by a group called, which seized upon the pipeline as a physical manifestation of the sorts of decisions that the world needed to move away from if we're to avoid the worst effects of climate change.

"Ultimately if we're going to prevent large parts of the Earth from becoming inhospitable or uninhabitable in our lifetimes, we're going to have to keep some fossil fuels in the ground rather than burn them," Obama said, echoing that argument on Friday. The oil that would have moved through the pipeline, derived from tar sands, was more carbon-intensive than standard oil, making it a particularly important symbol.

By rejecting it, Obama gets to seize upon that symbol for himself. The decision adds onto his proposal to limit pollution from electricity generators, to increase fuel efficiency in automobiles and to work with other major carbon-dioxide-emitters like China to reduce emissions -- just in time for the international climate talks that begin in France at the end of the month. He gets to carry a flag that reads "NO KXL" with him to Paris and once he leaves the White House.

It's important to note, too, that the political downside is very, very small. Republicans would have hammered Obama for the excessive delay in approval, had the president decided to approve the pipeline's permit. There's a wide seam of partisanship that runs through climate change as a political topic, which is readily apparent in polling on the subject. Republicans aren't going to dislike Obama more after this decision, which most people saw coming anyway. But he gets to define himself and his party on a subject that could become enormously important over the coming decades.

While rejecting Keystone XL doesn't solve the problem of climate change -- and while Transcanada could try again with the next president -- approving it wouldn't have necessarily doomed the planet, either. The formal decision to reject the pipeline is best seen as political in the broadest sense: A statement from the president of the United States that climate change is a serious factor in its decision-making process. Since the issue of climate change became a critical one, it's a statement that has nearly been unheard in Washington.

And Barack Obama would appreciate if you remembered who said it.