Odds of Hanging On
Two words: re-election. Two more words: We don't know how to count.
Staying in this job is as simple as getting people to like you all over again (and again, and again). In our democracy, elected politicians are given their power by the people, and those people can just as easily take it away. Every two to four years they get that chance, which is why you'll have to hit the campaign trail. This can often be more difficult than the first time around, because the voters actually have results to compare to your original promises.
Any decision you made during your term in office, from parking ticket fee hikes to paving over a city park to building a shopping center, can come back to bite you in the honorable behind. So get ready to start shaking hands and kissing babies, because you're going to have to continually charm the pants off the Average Joe and Jane to make them forget about the bad stuff you did the last time they voted for you.