Why don’t Americans trust their government? It’s not because they dislike individual programs like Medicare. It’s more likely because they think the whole system is rigged. Or to put it in the economists’ language, they believe the government has been captured by rent-seekers.

This is the disease that corrodes government at all times and in all places. As George F. Will wrote in a column in Sunday’s Washington Post, as government grows, interest groups accumulate, seeking to capture its power and money.

Some of these rent-seeking groups are corporate types. Will notes that the federal government delivers sugar subsidies that benefit a few rich providers while imposing costs on millions of consumers.

Other rent-seeking groups are dispersed across the political spectrum. The tax code has been tweaked 4,428 times in the past 10 years, to the benefit of interests of left, right and center.

Others exercise their power transparently and democratically. As Will notes, in 2009, the net worth of households headed by senior citizens was 47 times the net worth of households led by people under 35. Yet seniors use their voting power to protect programs that redistribute even more money from the young to the old and affluent.

You would think that liberals would have a special incentive to root out rent-seeking. Yet this has not been a major priority. There is no Steve Jobs figure in American liberalism insisting that the designers keep government simple, elegant and user-friendly. Sailors scrub their ships. Farmers clear weeds. Democrats have not spent a lot of time scraping barnacles off the state.

Worse, in an attempt to match Republican rhetoric, Democratic politicians are perpetually soiling the name of government for the sake of short-term gain. How many times have you heard Democrats from Carter to Obama running against Washington, accusing it of being insular, shortsighted, corrupt and petty? If the surgeon himself thinks his tools are rancid, why shouldn’t you?

In the past few weeks, the Obama administration has begun his presidential campaign by picking a series of small fights with the Republican-led House over things like recess appointments. These vicious squabbles may help Obama in the short term by making him look better than Republicans in Congress. But they will only further discredit Washington over the long run. Life is unfair. Republican venality unintentionally reinforces the conservative argument that government is corrupt. Democratic venality undermines the Democratic argument that Washington can be trusted to do good.

Liberalism has not expanded because it has not had a Martin Luther, a leader committed to stripping away the corruptions, complexities and indulgences that have grown up over the years. If you’ll forgive some outside advice, President Obama might consider running for re-election as Luther. It’s not enough to pick a series of small squabbles and then win as the least ugly man in the room. He might run as someone who believes in government but sees how much it needs to be cleansed and purified.

Make the tax code simple. Make job training simple. Make Medicare simple. Every week choose a rent-seeker to hold up for ridicule and renunciation. Change the Congressional rules. Simplify the legal thickets that undermine responsibility.

If Democrats can’t restore Americans’ trust in government, it really doesn’t matter what problems they identify and what plans they propose. No one will believe in the instrument they rely on for solutions.