WASHINGTON — Despite the growing international condemnation and isolation incurred by the government of Prime Minister Binyamin Netanyahu, the right-wing leadership of the so-called “Israel Lobby” here is riding high in the U.S. Congress.

So far this week, it has chalked up a key victory on Capitol Hill in its longstanding effort to impose “crippling sanctions” against Iran.

It also succeeded in getting a large majority of U.S. lawmakers to fire a shot across the bow of the government of Prime Minister Recep Tayyip Erdogan, which has led the international chorus of criticism against the Jewish state since the deadly Israeli seizure in international waters of a Turkish vessel carrying humanitarian supplies to Gaza.

While privately critical — often scathingly so — of Israel’s recent behavior, especially the May 31 commando raid, top officials of the administration of President Barack Obama are increasingly reluctant to air their complaints in public lest they harm Democratic prospects for retaining control of both houses of Congress after the mid-term elections in November.

Indeed, Obama will himself host Netanyahu at the White House in what is being billed as a “kiss-and-make-up” session Jul. 6 designed to reassure Jewish voters, in particular, that the two leaders’ contretemps over Israeli settlements in East Jerusalem earlier this spring has been put behind them.

Obama, according to some reports circulating here, hopes to receive a return invitation from his guest to visit Israel in October, a month before the November elections here.

Despite their relatively small number — about two percent of the total U.S. population and about three percent of voters in most elections, Jewish Americans are major donors to political campaigns, accounting for as much as 25 percent of all financial contributions to national campaigns and as much as 40 percent of all contributions to Democratic candidates, in particular.

They are also widely — if often mistakenly — seen by political candidates as virtually unconditional supporters of Israel prepared to reward or punish candidates based on their positions on the Jewish state.

“Every Democrat assumes that the biggest discernible group that contributes to their campaign is Jews,” according to M.J. Rosenberg, a Middle East analyst who worked for the most powerful lobby group, the American Israel Public Affairs Committee (AIPAC), in the 1980s.

“…(I)f a donor has a Jewish name, or is known to be Jewish, the assumption is that he or she is pro-Israel and will be offended by any deviation from the [lobby’s] line,” he said.

At the same time, harsh criticism of Israel by the administration risks mobilizing the Christian Right, a major constituency of the Republican Party, whose support for Israel’s ruling Likud Party and Jewish settlements in East Jerusalem and the Occupied Territories is based primarily on its theological views.

Thus, with the mid-term elections less than five months away and a succession of polls predicting major gains for Republicans in both houses, Obama and senior Democrats appear eager to avoid clashing with Israel, an impression that AIPAC and its allies are using to maximum advantage on Capitol Hill.

Under pressure from the lobby, the Democratic leadership in Congress Monday approved sweeping sanctions legislation aimed at third-country companies that do business with Iran without granting Obama the kind of flexibility in implementing the sanctions — particularly as they apply to Russia and China — that he had sought.

While the White House indicated Tuesday that it still hopes to work out some changes in the bill before Obama agrees to sign it, the fact that the administration’s own lobbying efforts had failed to bring along top Democratic leaders on the issue marked a major victory for AIPAC and its allies.

“AIPAC applauds toughest Iran sanctions ever proposed,” crowed the group’s press release after the joint announcement by the leaders of the “conference committee” that was charged with reconciling the differing — and weaker — versions of the sanctions bill that were passed earlier this year by the Senate and the House of Representatives.

“It provides the best hope that political and economic measures can peaceably persuade Iran to end its illicit nuclear program before it is too late,” the statement added.

In what many observers saw as a similarly impressive display of the lobby’s strength, 87 of the 100 senators signed an AIPAC-backed letter to Obama that not only supported Israel’s blockade of Hamas-controlled Gaza, but also defended Israel’s efforts to enforce it, specifically its attack on the Turkish vessel.

Nine Turkish activists, including one who was also a U.S. citizen, were killed after Israeli commandos opened fire when they encountered resistance to their attempt to board the ship during the night.

“Late last month when Israel learned that groups operating in Turkey wanted to challenge its blockade of Gaza, Israel made every effort to ensure that all humanitarian aid reached Gaza without needlessly precipitating a confrontation,” according to the letter that was jointly circulated by both the Senate Majority Leader, Harry Reid, and the Minority Leader, Mitch McConnell.

“Israeli forces were able to safely divert five of the six ships challenging the blockade. However, video footage shows that the Israeli commandos who arrived on the sixth ship, which was owned by the Turkish Humanitarian Relief Foundation (the IHH), were brutally attacked with iron rods, knives, and broken glass,” according to the letter, which uncritically recited the version of events propagated by the Israel Defence Forces (IDF). “They were forced to respond to that attack and we regret the loss of life that resulted.”

The letter went on to “recommend” that the administration “consider” adding the IHH to the list of “foreign terrorist organizations” and noted that the signers “have additional questions about Turkey and any connections to Hamas.”

Indeed, some lawmakers most closely associated with the lobby have since called for the administration to suspend military ties with Turkey or to seek its expulsion from NATO.

The letter also “deplore(d)” a resolution approved by the U.N. Human Rights Council (UNHRC) that called for “an independent international fact-finding mission” to investigate the incident, adding that Israel, which announced its own investigation, “has the right to determine how (it) is conducted.” “AIPAC strongly applauds the U.S. Senate’s overwhelming statement of support for Israel’s right to self-defense in the wake of the Gaza flotilla incident and its call on President Obama to continue standing shoulder-to-shoulder with Israel at the United Nations, as Democratic and Republican presidents have done since the birth of the modern Jewish state,” the lobby group said in a release Thursday that also commended a companion letter circulated by the House leadership and signed by more than 315 of the chamber’s 435 members.

“Addressed to President Obama, both letters state emphatically that the United States must continue to stand with Israel in every international forum because it is in America’s ‘national security interest’,” according to AIPAC which stressed the importance of conducting an investigation into “the Turkish terrorist-linked ‘charity’ that led the flotilla.”