The Modern Orthodox?
How about those on the political Right or Left?
So who exactly will go to Heaven?
Good Jews, and good non-Jews.
Heaven does not know of people based upon denomination or political party - it knows only of God's people, and goodness.
The opening to Pirkei Avot (Ethics of the Fathers) states, "Kol Yisrael Yesh Lahem Cheilek La'olam Haba" - all Israel has a share in the World to Come. They base this teaching on the verse from Isaiah 60:21, which references the righteousness of the Jewish people. This is not because we are inherently better than non-Jews; it's only because of God's kindness. God judges all people by their actions, but has graced us with the assurance that we will be rewarded for being His representatives here on earth (as long as we don't engage in one of the extreme sins that causes us to lose that distinction). In addition, all decent and ethical non-Jews will go to Heaven. Our understanding of God is that He is a just and merciful Creator, who will rightly reward anyone for the good deeds they have accumulated during their lifetime.
Unfortunately, the Jewish concept of the afterlife is often misunderstood. In fact, there are many who actually think that Jews don't even believe in an afterlife. However, this is only because we do not overly concern ourselves with it. The next world is not our primary focus because we have so much to accomplish while still in this world. Nevertheless, it's important to remember that the ultimate test for human beings is ethical - not theological. To the best of my knowledge, Judaism is the only major religion which has always maintained that actions determine one's eternal destiny - not theology. It's all about behavior.
However, if all Jews are guaranteed a place in Heaven, what incentive is there to perform any good deeds? The Chofetz Chaim answers this by way of a parable. There was once a wealthy businessman in Russia named Yisrael Brodsky, who employed hundreds of people. He was also a philanthropist who supported many Torah institutions, as well as relatives and community members whose finances had taken a turn for the worse. All the people he supported received a monthly check. One day, Mr. Brodsky came to visit one of his factories. The managers showed him around and introduced him to many of the workers. When Mr. Brodsky approached one of the people (who happened to be a non-working relative) and asked what he did there, the man replied, "I take a check." Everyone broke into laughter. The Chofetz Chaim concluded that such will be the case in the World to Come. Any Jew who claims their share solely because they happened to be Jewish will suffer an eternal embarrassment.
While all Jews have a spot in Heaven, the level of that share is dependent upon what we achieve during our lifetimes. The greater the actions, the greater the reward. The primary message for all of us is to simply do what is right, and God can be trusted to reward us with exactly what we deserve when our time on earth is done. Another lesson is that if Heaven's standards find it unnecessary to distinguish between Jews, then why is it that we so easily separate each other based upon anything other than objective ethical concerns?
Ironically, we can rectify our mistreatment of fellow Jews by more closely following Heaven's guidelines here on earth.