Balance is vital to complex systems — and government is a prime example.

Until humans resolve what constitutes the good life, and how we can collectively achieve it, we will need — some would say we’re stuck with — a two-party system.

In the American system, the major parties are not normally monolithic entities pledged to a single set of issues, with a prescribed position on each. In the 1980s, Democrats came dangerously close to mandating orthodoxy on abortion, with anyone not prochoice under severe pressure to conform.

More recently, it’s been the Republicans with the orthodoxy problem. The GOP’s moderate wing, in the U.S. Senate, is down to just two members, Maine’s Olympia Snowe and Susan Collins.

The problem goes well beyond electoral wins and losses, though they’re the ultimate litmus test in politics. When a party takes a drubbing — as Republican did in 2006 and 2008 — it must shift position to regain credibility.

But with the current one-wing GOP, the only way it can move is rightward, however fraught with peril. Hence Rep. Paul Ryan’s budget plan, which has as its centerpiece turning over Medicare to private insurers.

If President George W. Bush’s central second-term initiative, investing individual Social Security accounts in the stock market, was a dud — it was never even introduced in Congress — then why does Ryan think seniors want to turn over their health care to Aetna, Cigna and Anthem?

At least back then the stock market was booming and voters might have had illusions about “safe” investments. Now, there’s no indication more than a tiny fraction of seniors would trust their health to for-profit insurers.

But it’s the tax component of Ryan’s plan that makes it not just dubious, but risible. Republicans, unable to prevent federal spending to avert a depression in 2009, have been sounding alarms about the deficit ever since.

So how does Ryan’s plan contain it? Through punitive health-care cuts to Medicare and Medicaid and — given GOP orthodoxy — hefty tax cuts for corporations and individuals that already have a sharply higher share of the national wealth. That the tax cuts cancel out much of the “savings” is never mentioned.

A similar version of the passion for tax cuts is contained in Gov. Paul LePage’s pairing them with state employee pension give-backs. LePage insists the budget must reduce pension costs by $410 million, while cutting taxes by $203 million.

State employees have done the math, and came up with their own position, which — unusually — they announced at the onset of collective bargaining.

State workers are willing to freeze cost-of-living increases for a year, not three years, and cap any future increases at 3 percent rather than LePage’s proposed 2 percent. They also offered concessions on health insurance, a package amounting to $213 million in savings and a reduction of $1.2 billion in unfunded liability.

The message is clear: We’ll do our share, but don’t ask us to finance a major tax cut.

Finance Commissioner Sawin Millett, who normally keeps his cards close to the vest, was undoubtedly speaking for the governor in portraying the full $410 million as sacred, saying “Anything that falls short of that is a nonstarter.”

One wonders. While administration officials continue to make references to “shared sacrifice,” the numbers don’t support them. The state wants to reduce its retirement contribution and increase the employee share by exactly the same amount. This is not sharing. State workers, past and present, must atone for all past “borrowing” by the Legislature, failures to accurately project costs and recent stock market losses.

Under Gov. John Baldacci, Maine was among the few Northeastern states that did not raise taxes amid a punishing recession. Not even New Hampshire did that. The idea that now, with job recovery barely under way, we must cut income taxes to benefit those who are, by definition, doing better than everyone else, is hardly persuasive.

Cuts in state pensions have been enacted in Wisconsin, Ohio and Indiana; but those states, unlike Maine, don’t require two-thirds to pass a budget.

It’s hard to see why a single Democrat would vote for LePage’s budget, and many are needed in the House. Some Republicans, too, are feeling queasy, as they explain to constituents why tax cuts can’t wait until the state gets its financial house in order.

Whatever Millett says today, there’s a lot of ground to cover before the Legislature signs off. Yes, the shift to the right worked just fine in 2010. But unless human nature has been repealed, voters will be looking for a different direction two years hence.

Douglas Rooks is a former daily and weekly newspaper editor who has covered the State House for 25 years. He may be reached at drooks@tds.necom.