When Congress allowed a moratorium on offshore oil drilling to expire this fall, the Democratic majority’s intent was clear: It was a temporary move to silence Republicans who’d been hammering them over high gas prices, and the decision would likely be revisited come January.

Now, however, the outcome of the 2008 Senate elections could change that calculation. Most of the seven incoming Democratic freshmen support drilling – some made it a key point on the campaign trail — and it does not appear that party leaders will have enough votes to reinstate the sweeping ban. If any offshore moratorium is to advance, it will likely have to be far more limited than the old one.

In many ways, the drilling debate captures one of the Senate leadership’s biggest challenges in the next Congress: how to manage an expanded majority that includes a growing group of moderates who may differ with the Democrats’ dominant liberal wing on some key issues.

“Some of these issues will take some time,” said Majority Whip Richard J. Durbin of Illinois. “We’re certainly going to have to work with [new moderates] to find out how their priorities fit with ours.”

The newcomers will join a group of at least eight returning moderates who have demonstrated a wariness toward big spending and tax policies they view as bad for business. Some also favor a more muscular national security policy than the liberal core of the party.

Domestic energy production is not the only policy that the Senate moderates are expected to influence. Congress will tackle numerous big-ticket items during the administration of President-elect Barack Obama , including a health care overhaul, an economic recovery package costing hundreds of billions of dollars, major tax code revisions and climate change legislation.

“We won’t sacrifice our principles,” Nebraska’s Ben Nelson warned. “I hope there will be opportunities to seek consensus.”

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