Ignoring the premise of your question, because it would break the 20-year rule, there's A LOT to the US-Israel relationship besides an ideological commitment to a Jewish homeland. So much, in fact, that the Jewish homeland bit is pretty low on the radar at this point in time, though it wasn't when the state was first founded.

When the US became the first country to officially recognize the State of Israel, it wasn't so much about Jews getting a homeland in principle (Jewish residents of then-British Palestine had been angling for American support in obtaining one which the US had had no interest in giving), but about the effects of the Holocaust. The former US Ambassador to Israel (and major negotiator at Camp David between Israel and Egypt) Samuel Lewis breaks down the rationale for the recognition of Israel into six parts. The first is guilt- the US had nearly closed its borders in 1924 as part of the Johnson-Reed Act of 1924, which was specifically written in such a way as to exclude the European Jews who later were murdered in the Holocaust, and thereafter actively blocked bills which would allow more Jews to emigrate as the situation got worse and worse for them. The second is humanitarian- a Jewish state would provide a place for the hundreds of thousands of Jews in European DP camps (all the better that that place was not the US!). The third is politics, as there were many American Jews lobbying for the state (especially given what they knew about the Holocaust that had just occurred and murdered many of their family members)- a famous story is that Eddie Jacobson, President Truman's former business partner back in Kansas City, came to him to lobby. The fourth is idealism- Israel was being created with a democratic mission statement that greatly resonated with American politicians, especially in that region. The fifth is the religious/Judeo-Christian element of creating a Jewish homeland in the Land of Israel. The sixth, Lewis argues, is an ignorance of the history of the Arab populations in the area and the turmoil which would ensue from the declaration of the state.

He then says that the seventh is the "strategic relationship" between the US and Israel- but that that special relationship didn't exist until many years after the founding of the state. This is very much backed up by the State Department research document I looked at, in which I looked for discussions of US-Israel relations from before the 1970s and found nearly nothing. And in fact, Lewis says that the strategic relationship did start in 1970 with the Black September PLO challenge of King Hussein of Jordan. Before that, the US-Israel relationship was quite distant. While people were generally sympathetic toward Israel, the US government gave it little regard. No Israeli president was received in Washington until the Johnson administration, and most interactions with the US were in the form of castigation- Eisenhower was furious with Israel after the Sinai Campaign, and JFK had a standoff with Israel over his desire for US inspection of Dimona's nuclear facilities. While American Jewry often gave private economic aid to Israel, the US gave nothing.* There was no military funding either- Israel's arms came from France. The US preferred to prioritize its good relationships with the Arabs surrounding Israel, especially regarding Saudi Arabian oil.

It wasn't until the late 60s and 70s that the US developed a closer relationship with Israel in the interests of promoting peace in the region, giving Israel assurances of security in exchange for withdrawals from areas like the Sinai. This was seen not in isolation but in the context of US-Soviet relations, and the US talked about it more than they actually did anything concrete. It wasn't until 1973, for example, that the US gave Israel military aid. Israel was seen very positively in the US, especially compared to Vietnam, another US ally which was collapsing and bringing the US down with it. This changed with the Carter presidency (and here I'll mention that Lewis worked under Carter and so is both close to the situation and somewhat biased)- the resolution of the Arab Israeli conflict (or as it was coming to be known the Israeli Palestinian conflict) became a goal in and of itself, in the interests of obtaining peace in the Holy Land. Israel was seen as more of a burden or liability than anything else, and overt support was thought to have the potential to jeopardize the US's relationship with Israel's neighbors. And as much as the US was increasingly giving financial and military support to Israel, there were just as many intense disagreements over Israeli withdrawal from the West Bank and Gaza.

By the 80s, Reagan was the first to really refer to Israel as an ally. While previous conventional wisdom had been that the US couldn't publicly support Israel and the surrounding Arab nations, Reagan's administration challenged that and proved correct- to this day the US maintains relationships with countries throughout the region. This includes an economic relationship, as Israel and the US now have a free trade agreement and the US is now Israel's #1 trading partner (Israel is the US's #24 trading partner). At that time, while the US-Israel relationship was growing stronger, the depiction of Israel in the eyes of Americans was souring as it began to increasingly be perceived as an aggressor against Palestinians. While Reagan's government did not focus on working toward peace, the Bush and later Clinton governments did, with Israel also working toward peace processes until 1996, with the ascension of Netanyahu - and there we (coincidentally, as the Lewis article was printed in 1999) reach the end of the 20 year rule.

Historically, the US has, since the seventies, been serving as a mediator/arbitrator in the Israeli-Arab/Israeli-Palestinian conflict. Lewis gives a few reasons why he thinks this is so, as of 1999: wanting to stabilize the region due to conflicting interests in the area, it's a popular cause in the US (if it were to be actually achieved), wanting to prevent US intervention if a serious military situation breaks out, and accepting the interest of the parties in question in potentially arbitrating a solution. The thing is, in a situation in which on the one hand, the US government is supportive of Israel for reasons unrelated to the conflict, but on the other hand is trying to be even-handed in negotiating between Israel and Palestine/surrounding Arab countries, there can be a LOT of tension, and that's historically something that has bubbled up often. Lewis also points out an inherent Israeli contradiction that frustrates it- as a nation that was founded specifically for the purpose of Jewish self-determination and independence from other nations in a world in which dependence on others had meant the destruction of a vast portion of world Jewry, while the reality of US support is appreciated, the idea that it is needed is kind of frustrating, and Israel can still be distrustful of others' interests and influences. Both of these, along with massive cultural differences between the two countries, can create tension even at the times when the US-Israel alliance has been strongest.

Since the Johnson administration, probably the linchpin of US support of Israel has been of it as a liberal democracy in a part of the world in which this is rare, and that therefore the US interest is to promote this state of affairs. As part of this, the US has, since the Johnson administration, supported Israel's qualitative military edge (QME). The QME is the principle that since Israel is so much smaller in both land and population than even one of the many surrounding Arab countries which were historically its enemies, Israel should therefore have a military edge in terms of arms, protective devices and military technology in general to give it the ability to defend itself. This is one of the principles which has led to the giving of US aid, currently worth about $3bn a year (of which 74% goes back to the US in arms buys), to Israel. However, the QME doesn't prevent the US from also giving arms/funding/training to surrounding Arab nations, such as Saudi Arabia, Egypt, and Jordan, which it has done since 1981. So while the US retained its commitment to retaining the QME, the extent of the QME has definitely decreased over time. (It's gotten more complicated over time, but that violates the 20-year rule.)

In short- the US-Israel relationship is COMPLICATED, and while to give an answer that would explain the current situation is in violation of this sub's rules, way beyond my capability, and not at all something I'm interested in, hopefully this was helpful in some way.

(I would also like to quote from the introduction to Lewis's paper, which again I will repeat was printed in 1999:

Most non-Americans, and some non-Jewish Americans, attribute Israel's pride of place to the impact of Jewish political activism and campaign contributions and to the extraordinarily effective efforts of Israel's so-called "Jewish lobby" in Washington, led by [AIPAC]. At a time in US political history when... interest groups... and... campaign funds have an outsized effect on American politics, nobody can ignore the role they play in US-Israeli relations. But the story is much more complex.

Some things don't change, and that's as much as I'm going to say in relation to your actual question without breaking the sub rules.)

*As I was writing another comment, my research told me that the US DID give some money, mostly in the form of loans, to the State of Israel at the beginning of its existence. I'm going to do more research, but the majority of the money did indeed come from nonprofits funded by private individuals, or German reparations.

Naturally this is a very complex issue, which one could illuminate from a variety of quite different perspectives.

In order to examine the relationship of the U.S. with the present day state of Israel, we must go back to the events of the first half of the twentieth century.

Following the conclusion of hostilities between the Allied and Axis powers millions of refugees who had been brought to Germany as slaves or prisoners of war were held in Displaced Persons (DP) camps. Several million of those individuals were repatriated to their home countries. The Jewish population, however, had no homes to return to. They no longer felt safe in their native countries.

Many wished to travel to the British Palestinian Mandate, where they dreamed of establishing a Jewish polity, in which they would be control of their own destinies. Others wished to travel to the United States. The British were rather reluctant to admit Jewish refugees into Palestine, concerned as they were about brewing conflicts between Muslims and Jews. Efforts to immigrate the the United States were hampered by the fact the U.S. lacked a refugee policy in this era, and had quotas on the number of individuals who could immigrate from various European nations.

Complaints about the conditions of Jews residing in the Displaced Persons camps, many of which were re-purposed concentration camps where the refugees previously had been imprisoned, prompted the U.S. government to commission a report by Earl Harrison. His findings were extremely disturbing to President Harry Truman. I've linked to the report here. Among other things, he said "...we appear to be treating the Jews as the Nazis did, except we are not exterminating them."

Subsequently, the Truman Administration aligned itself with the views of the Balfour Declaration, which expressed support for a "national home for the Jewish people in Palestine." Displaced Jewish refugees were prioritized for immigration to the U.S.

This is perhaps the beginning of an answer that examines the origins of U.S. policy toward what would shortly become the State of Israel. One would also want to look at the Jewish population in the United States, and their natural sympathy toward their fellow Jews who had remained in Europe, which would express itself in organized support for refugees to travel both to the Palestinian Mandate and the United States.

In short, the United States has a legacy of support for the State of Israel that stretches back to the days of the Palestinian Mandate. There was a pervasive sense following the Second World War that the Holocaust must never be allowed to happen again. However, Jews could never feel at home in Europe. Therefore, they resolved to take the path of national self-determination, as nearly every other people of the world did who had the strength to assert themselves in the great dissolution of empires which followed the First World War. The United States, out of sympathy, and the demands of global hegemony, chose to support them in this endeavor.