Critics and supporters of the Keystone XL Pipeline are in agreement on at least one thing: Neither side is happy with how President Obama is handling the federal review of the project.

Monday marked both Earth Day and the end of the State Department's public comment period for the pipeline, which would carry oil from Canada to Gulf Coast refineries. But Obama's final verdict, which will upset either environmentalists worried about the pipeline's impact or labor unions eager for the jobs, may still be months away.

The White House sidesteps questions about Keystone, citing the ongoing review. However, analysts say Obama, not Secretary of State John Kerry, will have to decide whether the project proceeds.

"He's trying to delegate the blame to a lower level," said Peter LaFontaine, energy policy advocate at the National Wildlife Federation. "He's said some great things in speeches [about climate change], but if he says Keystone can go forward, he shows his priorities are elsewhere."

John Kerekes, central region director at the American Petroleum Institute, said that with the passing of more than four years since the pipeline was first proposed, Obama is running out of excuses.

"This is probably going to take twice as long as it will to build it," Kerekes said of the review process. "It's the longest pipeline review in history. It's been studied and studied -- and the same conclusions have been reached."

A draft report released by the State Department last month alarmed environmentalists with its conclusion that Keystone would not lead to a dramatic increase in greenhouse gases, one of the criticisms against the pipeline.

No matter his choice, Obama will alienate at least one of his core constituencies. Labor unions have backed the project, saying it would bring a much-needed infusion of new jobs. Green groups counter that endorsing the pipeline would undermine the president's second-term pledge to seriously combat carbon emissions.

Environmentalists on Monday pledged acts of "civil disobedience" in an attempt to sway the president. Protests have been staged at the White House, and more recently, at an Obama fundraiser in San Francisco.

"There is still time to convince President Obama to change his mind and reject Keystone XL," Becky Bond, political director of CREDO Mobile, said in a conference call with reporters. "This is going to be something where individuals are sending messages to the president that they're willing to go to jail."

Though the green lobby could influence his decision, an even more pressing factor could tip Obama's hand: the public. A recent Pew Research survey found that two-thirds of Americans support building the pipeline.

And Republicans are intensifying their focus on the issue as pressure mounts on Obama.

"A full year after staging a photo op in Oklahoma touting support for the part of the pipeline that doesn't require his approval," Brendan Buck, a spokesman for House Speaker John Boehner, told The Washington

Examiner, "the president needs to show some leadership, approve this project and allow these jobs to be created."