Updated 9:35 p.m.

President Obama’s hopes that the Senate would vote to support the military campaign in Libya seemed to be fading Wednesday. Instead, the same kind of discontent that led the House to rebuke Obama over Libya last week seems to be spreading to Congress’ other chamber.

Two senators on Wednesday introduced a resolution, which largely mirrors the one passed Friday in the House, stating that Obama “has failed to provide Congress with a compelling rationale” for the conflict. Legislators from both parties have criticized Obama for not obtaining congressional authorization before sending U.S. troops to join the international force against Libyan leader Moammar Gaddafi.

“This is unacceptable. This is an unacceptable way to treat a coequal branch of the United States government,” said Sen. Bob Corker (R-Tenn.), who co-sponsored the resolution along with Sen. James Webb (D-Va.).

The proposal includes a “sense of Congress” that the president should formally request authorization for the conflict. Also, like the House resolution, it would give Obama 14 days to provide Congress with detailed answers about why the U.S. entered the conflict.

“Without these answers, members of Congress are unable to assess critical questions,” Corker said.

Webb said, “The issue for us to consider is whether a president — any president — can unilaterally begin, and continue, a military campaign for reasons that he alone defines as meeting the demanding standards worthy of risking American lives and expending billions of dollars of our taxpayers’ money. It is important for Congress to step in and clearly define the boundaries of our involvement.”

Obama had previously expressed support for another kind of Senate resolution: one that would express support for the Libya campaign. That kind of resolution was introduced last month — but, on Wednesday, one of its key sponsors said it might never be voted on.

“A lot of colleagues feel that it’s not necessary,” Sen. John F. Kerry (D-Mass.) told reporters.

That decision may reflect a calculus that no debate over Libya would be better, from Obama’s perspective, than a debate that could invite senators to criticize him over Libya.

Obama sent troops to join the attacks March 19, and formally notified Congress on March 21. Under a 1973 law, the War Powers Resolution, Obama was supposed to obtain congressional authorization within 60 days.

But that deadline came last month, with no action from Capitol Hill.

In a news conference today, White House Press Secretary Jay Carney said that administration officials had consulted or briefed legislators on Libya 40 different times.

Carney indicated that the White House would respond, in some way, to the questions posed in the House resolution passed last week.

“We will answer the questions in that resolution, within the timeframe that [the resolution] specifies,” Carney said.

But it’s clear that the White House is not happy with these questions. A reporter asked Carney if he viewed the resolution from Webb and Corker in the same way he viewed the one passed by the House last week.

That is, as “unhelpful and unnecessary.”

“If it’s similar or precisely the same, then ... our reaction to it would be the same,” Carney said. “We have said from the beginning that we would support and appreciate expressions of support by Congress for the mission.”

Staff writers Scott Wilson and Ben Pershing contributed to this report.