Mr. Barr's proposal, introduced with no co-sponsors, moved with extraordinary speed through the legislative process.
The tax proposal introduced in Washington would not necessarily remain a flat levy.
The proposal introduced on Tuesday in some ways raises more questions than it answers.
The proposal introduced Tuesday would eliminate a provision that relates to certain asset-backed securities.
The new legislation builds on a failed proposal introduced in 2013 following the Newtown shooting.
One of the depreciation measures mirrors a proposal introduced recently by Representative Eric Cantor of Virginia, the House majority leader.
Republicans called the proposal, introduced by Representative Lynn Woolsey, Democrat of California, an attack on American values.
The proposal introduced by the president calls for a 5 percent annual increase in fuel economy for cars from 2017 to 2025.
Indeed, the Senate continues to flirt with a retrograde proposal introduced by Lisa Murkowski of Alaska that would undermine the Environmental Protection Agency's authority to regulate greenhouse gases.
The proposal, introduced last week, was an attempt by Ms. Quinn's office to assuage concerns from advocacy organizations about a recent ruling by the Campaign Finance Board.
Instead, he has thrown his support behind a proposal introduced by congressional Democrats, which would raise the federal minimum wage to $12 an hour by 2020.
