BALTIMORE — Congressional Republicans who promise to keep up attacks on President Obama for his decision to deny a permit for the Keystone XL pipeline project stopped short on Friday of saying they will seek to exact a concession on that issue in upcoming talks on a must-pass bill to extend a payroll-tax cut.

“I’m there,” said House Energy and Commerce Committee Chairman Fred Upton, R-Mich., about the possibility of adding Keystone language to the tax package. But Upton, who is in Baltimore with other House Republicans gathered at their annual retreat on legislative strategy, said the payroll-tax negotiations already are complicated enough.

“You’ve got all those different lines in the sands for different members … a couple of critical issues for the entire [House GOP] conference,” said Upton.

In fact, Upton suggested there might even be some political gain for Republicans in stoking the issue through the election-year summer, when, he noted, the public might connect the Keystone fight with what some are predicting could be a climb in gasoline prices to above $5 a gallon.

Upton is on the conference committee that next week is to begin talks on extending the payroll-tax holiday, federal unemployment benefits, and Medicare physician reimbursements beyond their end-of-February expiration. But both he and House GOP Leadership Chairman Greg Walden of Oregon, also a conferee, said on Friday that no decision has yet been made by House Republican leaders on whether to push action on the Keystone pipeline as part of the talks.

Walden said one option that is being looked at is trying to attach Keystone-related legislation to an eventual payroll-tax conference report. One such bill, sponsored by Rep. Lee Terry, R-Neb., would take the Keystone permitting decision out of the hands of the State Department and give it to the independent Federal Energy Regulatory Commission, a move Republicans argue would limit the role of political concerns in the issue.

As things now stand, they argue that Obama’s decision this week was intended to get him past the election, so he would not have environmental groups angry at him. “I mean, that’s how I read it,” Walden said.

But in suggesting why Keystone-approval may not be pushed as part of the payroll-tax negotiations, Upton said there already are other big, complicated issues involved in those talks that are important to House Republicans—such as unemployment reforms and wanting the package to be completely paid for. And he said there have been no discussions yet on the idea with Senate Republicans.

But Upton said Republicans intend to keep Keystone “on the front burner.”

As part of that, he said his committee is holding a hearing on Wednesday, the morning after Obama’s State of the Union speech, where a State Department official will testify regarding the administration’s Keystone decision.

At a later news conference in Baltimore, House Speaker John Boehner, R-Ohio, would not answer whether he would push the payroll conferees to take up the Keystone matter. But Boehner said, “We’re going to do everything we can to try to see this project initiated. And I will be working with the rest of our team, Chairman Upton, to look for every opportunity we can to advance this idea.”