One is the Supreme Court. That is obvious and often discussed.
The other is every bit as important, but I haven't heard it discussed at all.
The economy is recovering. That is clear. The next 4 years are going to be better than the 4 post-Bush years no matter who is President. Obama endured the pain of the Bush train wreck and has put us on a good course. The very worst thing that could happen is for a Republican to get in there and enjoy several years of relative prosperity. They would claim THEY were the ones to turn the economy around.
Obama must get 4 more years. Democrats have paid a dear price to do what is right for the country and the economy. We deserve to get credit for that over the next 4 years.
And if that does happen, there will be the clearest possible track record. 8 years ending in prosperity under Clinton. 8 years ending in disaster under Bush. 8 years ending in prosperity under Obama.