Centrists get a lot of flak from both the left and the right for supposedly being middlemen who have no spine and can't pick a side or form distinct values. But that's not entirely true. Centrists, at least certain centrists, do have core values: classical liberalism. Classical liberals are essentially centrists. They always have been and always will be. Because classic liberalism cannot hold, it cannot maintain itself forever.
Classical liberalism is an unstable structure. Even if you establish a classically liberal government, as perhaps the Founding Fathers did, society will not remain classically liberal forever. It will forever swing back and forth like a pendulum between the left and right, more progressive and more conservative.
Centrists do have a spine. They have true values that they're trying to establish and preserve. But depending upon where the pendulum of power has swung presently, they will find themselves on either the left or the right of the status quo. Furthermore, they will also have enemies to both their left and right, no matter which side is in power at the moment.
Maintaining that foothold of the center, of classical liberalism, is always difficult, because there's only ever a brief window during the swing of the pendulum where classical liberalism is in favor by the majority before it continues swinging further to the left or right. So classical liberals must always be fighting to bring that pendulum back towards the center, even though it cannot stay there forever--society will always swing. They can work to mitigate the swings so they're less severe each time, and try to slow the pendulum to stay in the center longer. But the pendulum of culture will never stay classically liberal permanently.
It is much easier to be on the left or right, where you have a clear team and a clear enemy. You're only fighting one side in an all-out culture war. Whereas trying to be a centrist classical liberal is fighting a culture war on two fronts--at all times. So centrists should not be dismissed as spineless, at least those who are sincerely fighting for classical liberalism with integrity. It is not a mere cop-out, taking the easy way out by settling between the two sides of the culture war. (Though some "centrists" do this and are indeed spineless and should be condemned.) But classically liberal centrists have chosen the most difficult position because they are not choosing to compromise between the left and the right; rather they are actively fighting both the left and the right at the same time.