An open question is whether House Republicans will balk on an overall transportation bill if they can't get Keystone. Similarly, despite their public statements, it's unclear ray ban sunglasses sale whether Senate Democrats would be willing to sacrifice the bill in order to block a Keystone provision, and whether Obama would follow through on his veto threat, especially if the Keystone language were softened in negotiations.

The president painted a bleak picture of America's infrastructure in a speech Monday to union workers in the construction industry, saying U.S. highways are clogged, railroads are no longer the fastest in the world and airports are congested. A transportation construction bill would boost employment and the economy, but "the House Republicans are cheap ray ban sunglasses refusing to pass a bipartisan bill that could guarantee work for millions of construction workers," Obama said, referring to the Senate bill.