Congress needs to find $1.2 trillion by the end of the year to avoid the potential sequestration cuts that are scheduled to take effect. In other words, Congress needs to cut the Federal budget by $1.2 trillion. However, to do so would require devastating cuts across the board, having a detrimental impact on all aspects of the government, including defense, national security, and core government functions.
According to the Congressional Budget Office, the estate tax increases that will go into effect on January 1st will potentially bring in $500 billion, over the next 10 years. The Democrats want these increases to go into effect in order to avoid the massive cuts. But the Republicans do not want these tax increases (and others) to go into effect. With opposing positions, and the lack of compromise between the two parties evident over the past few years when it comes to significant budget decisions, it will be interesting to see how this plays out over the next three months.
The article linked below has a good description of the recent history of the estate tax and the impact of the increases that will potentially take effect on January 1st.