What is the reason why the United States is so generous in supporting Ukraine in the war?

What is the reason why the United States is so generous in supporting Ukraine in the war? In fact, the United States also has its own ideas. After all, Ukraine lost the war, and Russia will occupy a lot of Ukrainian territory. On the contrary, Russia is stronger, closer to Western Europe, and more threatening European security. Therefore, the United States should draw NATO together to help Ukraine, so that Ukraine can stand up and use it to consume Russia, The United States has always believed that Russia is a huge threat to the United States. If the war in Ukraine is left unchecked, Ukraine will not defeat Russia at all. Only by supporting Ukraine, Russia will not win Ukraine so easily. The successful counteroffensive of Ukraine in Kharkov and Kherson shows that the support of the United States is effective, so the United States will increase its support in 2023 to make the Ukrainian army stronger, Even support the Ukrainian army to attack Crimea.