"Instead of making the investments we need to get ahead, they're willing to let us all fall further behind," he said.
The transportation bill "is incredibly important to the president," said Ed Wytkind, president of the transportation trades department of the AFL-CIO.
Both sides ultimately must decide whether they want an issue to be used as a campaign weapon or an accomplishment they can tout to voters.
Dave Bauer, a lobbyist for the American Road and Transportation Builders Association, cautioned against reading too much into what congressional conferees say at this point.
"Before they even get to a conference table, some seem to be trying to make this all about Keystone, and it's not," he said.
Follow Joan Lowy at http://www.twitter.com/AP_Joan_Lowy
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.