The word "Pharisee" is rather common in modern speech. It usually means hypocrit, or self-righteous, or the like. We get this characterization from the Gospels, where the Pharisees seem to be the principal opponent of Jesus and his message. Turn to Matthew 23 and you will find all the vitriol that Jesus can muster against them. "You snakes, you brood of vipers! How can you escape being sentenced to hell?"
No such words for the Sadducees. The one time Jesus seems to interact with them at all, it is merely to respond to a riddle by which they hope to trip him up in his belief in the resurrection of the dead. All in all, they seem very minor characters. The Pharisees are the real bad guys.
And so I see many attacks on conservative Christians as "Pharisees." They maintain traditional beliefs about sexuality, marriage, and abortion. For such views they are branded as self-righteous bigots, the kind that Jesus most fiercely chastised.
Yet in the Bible, those closest to God get the fiercest treatment. The prophets speak judgment against Israel's neighbors, yes, but the harshest critiques are reserved for Israel, and even more so for Judah and Jerusalem. It is important not to get too close to God, for he is "a consuming fire," as the people learned from Mount Sinai. They were so afraid after having heard the words of God, they didn't want to hear any more, and God told Moses they were right to think that way. Those who are closest to God have the greatest responsibility. And so Moses, the man who spoke to God face to face, was kept out of the promised land for the slighest offense (he hit the rock instead of speaking to it).
It is not a coincidence, then, that Jesus ends up alone. The ones who hand him over to be crucified are the ones who are closest to him--that is, the Pharisees. But even his own disciples abandon him--and one of them is a traitor. Although it is the Romans who actually kill him, it is those who should have been with him from beginning to end who receive the condemnation of Scripture. That is because the Scriptures are written for them, both as an offer of reconciliation and as a warning. It is our heart's greatest desire to be close to God; but the closer we are, the more it hurts to have our sins purged from us.
The Romans receive no condemnation whatsoever in the Gospel narratives; there is no need, for they are very far from Jesus. (Pilate reveals just how far with his famous question, "What is truth?" The Pharisees would never have asked such a question.)
The Sadducees, too, are far from Jesus. No, he doesn't call them hypocrites, or blind guides, or whitewashed tombs, or snakes, or brood of vipers. But he says to them, "You know neither the Scriptures nor the power of God." What more is there to say?
Importantly, when Jesus responds this way to the Sadducees, the Pharisees gather together around him. They ask him what is the greatest commandment. And Jesus affirms exactly what they believe: Love the Lord your God, and love your neighbor as yourself. The Pharisees do know the Scriptures and the power of God. They are not far from the kingdom.
It is their very proximity that earns them the greatest condemnation. "Woe to you, scribes and Pharisees, hypocrites! For you lock people out of the kingdom of heaven. For you do not go in yourselves, and when others are going in, you stop them." (Mt. 23:13) They are standing at the very gate, but they refuse to go in; worse, they refuse to let others go in.
So naturally this is a very serious warning for traditional Christians, who take righteousness seriously, as the Pharisees did. Those who are closest to God are closest to the fire of condemnation. If we wish to be pure in heart, so that we may see God, we must suffer the most. In some sense the Bible condemns the righteous even more than sinners.
But for those liberal Christians who think they are on the right side because they don't find Jesus condemning their position, I'm afraid they have it all backwards. To them Jesus simply says, "You know neither the Scripture nor the power of God." Of course Jesus is not offended by those who have completely abandoned the traditions of the church. He is only hurt by those close to him. He is hurt the most by his true disciples.