The State Department has mounted an intense lobbying effort to derail a measure that would essentially classify Saudi Arabia as an outlaw regime, as House Democrats seek to exploit what they consider a potentially embarrassing alliance cultivated by the Bush administration in the war on terror.

The battle has unfolded through repeated attempts by Rep. Anthony Weiner (D-N.Y.) to attach the language to spending bills on the floor. His measure would add Saudi Arabia to the official list of state sponsors of terrorism, linking the desert kingdom with such disfavored regimes as Iran and North Korea.

The most recent attempt was in October, during consideration of emergency spending for ongoing operations in Afghanistan and Iraq.

Weiner’s amendment drew nearly 50 more votes among Democrats than it had in July, when it had last been debated. But this was countered by a roughly 50-vote swing in the other direction among Republicans, who faced strong pressure from the State Department.

“They’re going to the wall for the Saudis on this thing,” Weiner said of State, citing lobbying by Deputy Secretary Richard Armitage that went into the wee hours of the morning of the vote. “They’ve been going crazy about this.”

A letter circulated before the latest vote by Assistant Secretary of State William Burns said the measure would “severely undermine” efforts to work with the Saudis “at precisely the moment when it is moving to a new level of effectiveness.”

Saudi Arabia’s role — or lack thereof — in combatting terrorism has been a source of great confusion and consternation on Capitol Hill in the past two years.

While President Bush has routinely cast the Saudis as important allies in the war on terror, many Members from both parties have noted the putative Saudi origins of the financing, anti-Western militancy and the militants themselves — not least the 15 Saudis who were among the 19 hijackers on Sept. 11, 2001.

Weiner and other Democratic sources suggested the administration’s solicitousness toward the Saudis amounted to a political gift basket for the Democrats — an opportunity to suggest the administration, because of oil interests, has treated the kingdom with kid gloves during the war on terror.

The measure also provided an opportunity to drive a wedge between the GOP leadership and the Israel lobby, where the Saudis are seen as a primary source of funding for terrorist groups who attack the Jewish state. This was particularly true with Majority Leader Tom DeLay (Texas), who has established himself as a key ally of Israel, but had been forced by circumstances to lobby against Weiner’s amendment.

Weiner expressed annoyance that the Democratic leadership failed to recognize the political impact of his proposal until after the July vote, and thus did not try to build a critical mass of support for the measure until late in the game.

Support for the amendment grew from 110 to 160 Democrats in the October vote. Support among Republicans dropped from 80 to 32.

Conflicting messages about Saudi cooperation have left many Members working through their own calculus about whether the bad outweighs the good, or vice-versa.

“My sense is that Saudi Arabia has been more of a hindrance than a help since 9/11,” said House Chief Deputy Whip Eric Cantor (R-Va.), who was among those who backed Weiner on both votes. “The environment over there provides an opportunity for terrorists to operate and to flourish.”

A senior House Democratic leadership aide said at least two of the party’s Members on the Intelligence Committee suggested before the most recent vote that they “know [presumably exculpatory] things others don’t about Saudi Arabia,” and thus could not back Weiner’s measure. They discovered subsequently that everyone — including many who were going to support Weiner’s amendment — had the same information, the aide said.

State Department spokesman Adam Ereli said the Saudis have “picked up the pace” of their counterterrorism efforts since May 5, when al Qaeda launched a ferocious strike against the kingdom. He said it is important to make a distinction between Saudis involved in terror and the Saudi government.

“We would not say the Saudi government is so negligent, so unwilling to help, as to constitute complicity in terrorist activity,” Ereli said.

Ereli cited last week’s terrorist attack on civilian housing in Riyadh as evidence that the United States and Saudi Arabia are fighting the same battle.

“To say they don’t have the same view of al Qaeda and of terrorism flies in the face of the facts,” Ereli said.