Welcome to Behind the Lines, a weekly conversation with Salt Lake Tribune cartoonist Pat Bagley and BYU economist Val Lambson:

Bagley: With tax filing day just around the corner, I thought we could talk about the point of the whole painful exercise.

Lambson: We might start by remembering that it is not painful for about half of the 99 percent because they don't pay income tax. We might also recall that personal income taxes are only about 40 percent of federal government revenues, the rest coming from payroll taxes, various excise taxes and user fees, corporate income taxes and so on.

Bagley: I'd be curious to know how many of our Utah legislators don't pay income tax. Once you add up the child deductions, home mortgage interest deductions, charitable (tithing) deductions, various business deductions (travel, meals, entertainment), I imagine a goodly number of our fecund state representatives don't pay a dime of federal income tax.

And that's the problem; the tax code is too complex. The system favors those who can afford phalanxes of lobbyists and accountants and tax attorneys. Hence Romney pays 13.8 percent on his millions earned from investments while those who are too poor to pay income tax (presidential candidate Michele Bachmann called them "lucky duckies") still have a sizable portion of their meager incomes eaten up with sales, gas, payroll and property taxes.

Lambson: First, defining income is complex. Is a company car income? Should a personal car be deductible if you only use it for work-related travel? Is driving to your employment work-related travel? What if you stop to buy a loaf of bread on the way home? Should health insurance be taxed as income? How about frequent flyer miles? These are only a few of the more trivial examples of what the tax code must deal with. More serious issues make most eyes glaze over. (Anyone up for a discussion of straight-line vs. accelerated depreciation?) The system is ripe for manipulation and capture, and the result is that many of our brightest minds are involved in tax avoidance instead of something productive.

Bagley: All true. Some think a flat tax is the solution, but even that begins to resemble the swamp in my cartoon once you wade into the details. Still, someone needs to take a stab at rationalizing a tax code which seems to be accelerating the growing disparity of wealth in America. Obama hasn't come up with a comprehensive tax reform proposal (the "Buffet Rule" is a band-aid) and the GOP's refusal to raise taxes on anyone has them locked into supporting the worst features of the current system.

Lambson: A flat tax has its virtues, but simplicity is not among them. The problem of defining income is exactly the same. As for reform more generally, when tax rates are as high as necessary to fund government at its current scale, there are tremendous incentives for lobbying and manipulation. That is how we got into this swamp, after all.

Our readers outdid themselves in comment quality this week. Even though slippast had the top comment last week and claims to almost always disagree with me, I chose this comment from among many good ones.

When JFK ran, people were familiar with the Catholic Church. ... This time around Romney is confronting the same worry about church influence and the fact that the LDS Church itself is completely misunderstood around the country. That's not one but two steep hills to climb.