As the Israeli bombardment of Gaza enters its fourth day, there is no shortage of tests. The wisdom of Israeli strategy is being tested. The resilience of the Palestinian people is being tested. The ability of the U.S. and the international community to impose a ceasefire is being tested.

And the might of the new progressive American Jewish infrastructure that emerged in 2008 — unapologetically pro-peace and pro-Israel — is undergoing its own test as well: How to effectively argue that an Israeli war is counterproductive to Israel’s long-term security while the bombs are falling.

“Absolutely,” said Jeremy Ben-Ami, executive director of J Street, a new liberal Jewish lobby group. “This is a real testing moment for those of us who honestly believe you can be supportive of Israel but questioning of steps its government takes.”

M.J. Rosenberg, director of policy analysis for the Israel Policy Forum, another progressive Jewish organization, was similarly blunt. “It’s put-up-or-shut-up time,” he said. “For a two-state solution, for the U.S. to be an honest broker — if all of us just sit back and say, ‘Israel had no choice [to bomb Gaza], then we’re just a bunch of phonies. But I don’t see that happening.”

As is typical during moments of crisis in the Middle East, the bombing of Gaza quickly led to statements of unambiguous support for Israel from leading American politicians, including from Democrats and progressives.

“When Israel is attacked,” said Speaker of the House Nancy Pelosi (D-Calif.), “the United States must continue to stand strongly with its friend and democratic ally.” House Majority Leady Steny Hoyer (D-Md.) said, “Israel is acting in clear self-defense in response to heinous rocket attacks from Hamas-controlled Gaza.” Howard Berman (D-Calif.), the progressive chairman of the House Foreign Affairs Committee, at least acknowledged the 364 Palestinians killed in Gaza over four days, but only to say, “The loss of innocent life is a terrible tragedy, and the blame for that tragedy lies with Hamas.”

The Gaza crisis is the first Israeli-Palestinian emergency since J Street launched in April. As a self-identified force to shift the American debate on Israel and Palestine to the left, it has not previously had to make its arguments while Israel has been at war. Usually, when Israel finds itself at war, “our side gets cowed into silence,” Ben-Ami, a former domestic policy aide to President Bill Clinton, told the Washington Independent in April. So Gaza is the first test for whether that silence can be broken, and the expected pro-bombing statements made by U.S. politicians and media commentators demonstrates its uphill struggle.

On Sunday afternoon, J Street emailed supporters and asked them to endorse a statement: “I support immediate and strong U.S.-led diplomatic efforts to urgently reinstate a meaningful ceasefire that ends all military operations, stops the rockets aimed at Israel and lifts the blockade of Gaza. This is in the best interests of Israel, the Palestinian people and the United States.”

The appeal was accompanied by an anguished email written by online director Isaac Luria. “At this moment of extreme crisis, J Street wants to demonstrate that, among those who care about Israel and its security, there is a constituency for sanity and moderation,” Luria wrote. “There are many who recognize elements of truth on both sides of this gaping divide and who know that closing it requires strong American engagement and leadership.”

By 5 p.m. Monday, the organization said it had collected 11,870 signatures. Ben Ami said he would present the petition to the Obama transition team, with which the organization is in talks about appointments to Middle-East policy positions.

For its part, the transition has been circumspect, declining to step on the Bush administration’s efforts before Obama takes office. “President-elect Obama is closely monitoring global events, including the situation in Gaza, but there is one president at a time,” said Brooke Anderson, the transition’s chief national-security spokeswoman.

Further steps, Ben Ami said, depend on whether the Israeli campaign winds down or escalates. But he said that the organization’s leadership would “do whole range of media” appearances in order to demonstrate that “this organization with strong roots in the pro-Israel community is willing to say, ‘Let’s discuss the best way going forward and not blindly go down a path we think is counterproductive.’”

Others discussed next steps already. Rosenberg anticipated forming a coalition with organizations like J Street and Americans for Peace Now, another progressive Jewish lobby group, as well as progressive Arab-American organizations like the American Task Force on Palestine — which has also called for an immediate ceasefire in Gaza — to coordinate messaging and lobbying.

While coordinated efforts have not yet coalesced, some in the progressive Jewish community think that the “message is getting out there,” as Ori Nir, spokesman for Americans For Peace Now, put it. “It’s getting reported by Jewish and general media, getting it out to our base,” Nir said. “We sent out yesterday our statement and today an action alert calling on activists to send letters to President Bush urging what the press statement urged, and to President-elect Obama.”

In the statement, Americans For Peace Now’s president, Debra DeLee said, “While we hold – as we always have – that Israel has the right and the obligation to protect its citizens from attack and threats, we know that military power alone will not provide real, long term remedy for the threat that the Hamas-ruled Gaza Strip poses to Israel. Israel needs stability on its border with Gaza. Such stability can only be achieved through a political process,” a sentiment echoed by organizations like J Street and the Israel Policy Forum.

Hussein Ibish, a senior fellow with the American Task Force on Palestine, urged progressive Jewish organizations to “be very clear with their Israeli friends that there isn’t going to be a military solution [to the conflict], just as we are with our Palestinian and Arab friends.” But he cautioned that a moment of hostility might not actually be such a proving ground for the new liberal Jewish lobbying apparatus.

“Peace groups on both sides are more fully tested when the spotlight is not on the process, counterintuitively,” Ibish said. “That’s when the hard work — building the basis of a negotiated agreement comes in. That’s the only way this ends, and you can’t bring that out in any meaningful when the bombs are flying.”