1. The flat tax: In the 2012 Republican presidential race, candidates including Rick Perry and Newt Gingrich proposed a flat tax on personal income. The idea seems likely to pop up again in 2016. Most flat-tax proposals are a version of a flat consumption tax devised by economists Robert Hall and Alvin Rabushka. If you were creating a tax code ex nihilo, the flat tax might well be the way to go. Simulations, not to mention common sense, suggest that a flat tax with a low rate would produce a larger economy than the current mess of a tax code does.

But we are not starting from scratch. It would be problematic to transition to a flat tax — at least at the 15–20 percent rate typically proposed — from a tax code that has nearly half of Americans paying no income tax. A flat tax would probably generate too little revenue, making budget deficits worse. One smart way to tweak the idea would be to keep the consumption-tax aspect while adding a more progressive rate structure.

2. The gold standard: The party platform adopted at the Republican National Convention in Tampa included a plan calling for the creation of a commission to consider restoring the dollar-gold link. Been there, done that. A similar panel established by President Reagan dismissed the idea. More recently, a University of Chicago survey of 40 economists found unanimous and vehement opposition to resurrecting the gold standard.

Those results are hardly surprising. The gold standard played a central role in the Great Depression and the severe deflation that accompanied it. Its return would hamstring the Federal Reserve in any effort it made to prevent future recessions from morphing into depressions. The latter, by the way, tend to usher in dramatic expansions in the size of government. A better option would be to anchor monetary policy not in stuff mined from the ground, but rather in futures contracts linked to market forecasts of nominal gross domestic product.