IT'S been said the two things a smart politician never forgets are the voters back home and who pays the tab for his reelection.In somewhat the same vein, Israeli Prime Minister Yitzhak Shamir showed in a swing through Boston Tuesday and Wednesday that he has not forgotten a key United States constituency, or the importance of selling State of Israel bonds to them. The diminutive Mr. Shamir was barely visible from behind the podium where he spoke, but his words came across loud and clear to a roomful of ardent Boston supporters of Israel who had come to buy bonds in denominations of $25,000 and up: "We have only one friend in this world.... We have our friends, the Jewish people." While headlines have centered on the $10 billion in US loan guarantees sought by the Israeli government, which President Bush has delayed, a smaller but similarly crucial fund-raising effort is under way. Despite the recession, the effort to sell Israel bonds has raised $800 million worldwide so far this year, up from $565 million last year. Seen as vital to the building of Israeli roads, homes, industrial, agricultural, and other infrastructure, the sales of bonds to financial institutions and to private and institutional investors have raised $11 billion since 1951. There is special urgency now, Israeli officials say, because the movement, or "aliyah," to Israel of an estimated 1 million Jews from the Soviet Union, Ethiopia, and other parts of the world is in full swing. But that country's rapid rise in population, expected to grow from 4 million people to the 5 million level before the end of the decade, has added strain to the country's finances. Banks and other lenders worried about Israel's credit worthiness are requiring guarantees before lending $10 billion to help settle the flood of immigrants. Shamir criticized Mr. Bush's decision to delay the loan guarantees before a crowd of cheering supporters in Newton, Mass. Later that day, Shamir told a room brimming with investors that "every day and night we [Israel] are getting stronger. Time works in our favor. Without such an immigration we will not have peace. If we have peace, it will be useless if we do not bring to our land all the millions of Jewish people who have to be there." Behind this fund-raising effort, however, was another Shamir aim: to rally the support of American Jews in advance of talks this week with President Bush about the next phase of the peace talks. Shamir, apparently anticipating pressure from the administration, late in the trip called on the White House to be "honest brokers" in the talks.