Security is always heavy around the annual policy conference of the pro-Israel lobby, the American Israel Public Affairs Committee, but with the presidents of the United States and Israel and the Israeli prime minister in attendance, along with an uptick in Iranian terrorism and a foiled Arab suicide bombing last month inside the U.S. Capitol, look for it to be even tighter this year.
The terror threat will reinforce the message of AIPAC and Prime Minister Benjamin Netanyahu that will permeate the conference: Stop Iran Now.
AIPAC's annual forum March 4-6 is expected to attract a record-setting 11,000 to 13,000 activists to the Washington Convention Center, including some 400 individuals from the Philadelphia area.
Iran will also be high on the agenda during a meeting between Netanyahu and President Barack Obama that is slated for March 5, the same day as Netanyahu's speech to the AIPAC gathering.
Obama's greatest challenge will be keeping Netanyahu from turning the conference into a war rally aimed at tying American hands and giving Israel a free hand to attack Iran at a time of its choosing.
Republicans are barking at Obama's heels, accusing him of being too soft on Iran and too tough on Israel, and three GOP presidential hopefuls -- Mitt Romney, Rick Santorum and Newt Gingrich -- are telling Netanyahu he has their backing if he decides to attack Iran's nuclear facilities.
Iran has been AIPAC's No. 1 issue for two decades, and when its thousands of members spread out across Capitol Hill on Tuesday to lobby their senators and representatives, their top assignment will be getting sponsors for a new Senate resolution seeking to lower the threshold for going to war.
The non-binding resolution -- initiated by Sens. Joe Lieberman (I-Conn.), Lindsay Graham (R-S.C.) and Robert Casey (D-Pa.) -- aims to move the red line for an American attack from "acquiring" nuclear weapons to having the "capability." That is Israel's standard and it wants Washington to publicly adopt it as well.
The resolution stops just short of threatening military action, but Lieberman leaves no doubt what he has in mind. The message to Iran, he said, is, "you have only two choices -- peacefully negotiate" an end to your program or "expect a military strike."
Even more than in past years, the call to arms is meant to intensify pressure on Iran. Obama has said all options are on the table, but Republicans insist that's not enough -- for Iran to take the military threat seriously it must see visible preparations for an attack. They're telling Obama he should give full backing to whatever Israel decides.
That conflicts with what the Pew Research Center found in its recent polling. While 58 percent of Americans support using military force, if necessary, to prevent Iran from getting nuclear weapons, only 40 percent support such action by Israel and half would want to remain neutral if Israel does go it alone.
Obama will address AIPAC on Sunday and will stress America's "ironclad" commitment to Israel's security, his record of support and his determination to keep Iran out of the nuclear club.
When the two leaders meet Monday at the White House, the president is expected to tell Netanyahu that international sanctions are working and urge him not to attack Iran this year. Reports from both capitals say Obama will seek advance warning of an Israeli attack, and Netanyahu will turn him down.
Senior diplomatic, intelligence and security officials have been traveling back and forth between Washington and Jerusalem quite a bit lately. The Americans have been urging patience and the Israelis, at least at the political level, are saying it's later than you think.
Behind the unusual media coverage of these exchanges is said to be an American concern that their message isn't getting through in private so it is necessary to go public. And it's clear there is little trust on either side when it comes to Iran.
Netanyahu's message to AIPAC will pound home his theme that international sanctions aren't working. Without openly calling for military action, he will remind the audience that in the past week, the U.N. nuclear oversight agency reported that Iran has significantly expanded its uranium enrichment beyond levels required for peaceful production of energy and its inspectors were refused access to a key nuclear facility.
Obama has the strong backing of the former heads of Israel's security services, who share his opposition to a pre-emptive strike. And Netanyahu has the backing of Republicans trying to make support for Israel a partisan wedge issue in the presidential campaign.
Some observers in Israel and Washington say that if Netanyahu opts for an attack before November, it will be as much for political as strategic reasons. He is believed to feel that if he strikes before the presidential election, Obama, whom Republicans and some in the Jewish community accuse of not being supportive enough for Israel, would have little choice but to stand with him no matter how much the attack damages U.S. interests. But after November, it would be a far riskier game for the Israeli prime minister.
Netanyahu will have the AIPAC audience and many politicians cheering the war talk, but he also knows the American people don't want another Mideast conflagration. They can't ignore the danger of terrorism, attacks on American interest in the region, igniting an oil crisis and setting back the global economic recovery, all possible repercussions of an Israeli attack.
As he makes his decision about whether to strike Iran or not, Netanyahu also has to consider his country's security in terms of the long-range impact on bilateral relations if the American public blames Israel for dragging the United States into a war.