House Budget chairman Paul Ryan (R., Wis.) must have been one of those elementary-school kids who spent recess fine-tuning his homework while the other boys and girls climbed trees and yanked each other’s hair. Little has changed as many of those children won congressional seats. They are older, but hardly wiser.

“This plan would literally be a death trap for seniors,” shrieked Rep. Debbie Wasserman-Schultz (D., Fla.), Pres. Barack Obama’s recently designated Democratic National Committee chairwoman. Ryan’s economic blueprint, “The Path to Prosperity,” calls for “waging war on American workers,” screeched Rep. Xavier Becerra (D., Calif.).

Washington Democrats totally controlled Congress and the White House last year. Nonetheless, they dodged their duty to adopt a Fiscal Year 2011 budget, thus triggering today’s stopgap spending bills and government-shutdown talk. Meanwhile, Ryan’s comprehensive proposal would tame the tsunami of red ink that could drown America. He does this while cutting taxes, fueling entrepreneurship, and spurring economic growth. Still, he somehow is the bad guy who murders Granny and hurls grenades at laborers.

The juvenile reaction to Ryan’s measure is especially frustrating because his plan offers such a mature approach to America’s fiscal predicament. Indeed, “The Path to Prosperity” goes far beyond charts and spreadsheets. The inspiring rhetoric and patriotic allusions of Ryan’s manifesto advance cherished national virtues:

This budget offers America a model of government guided by the timeless principles of the American Idea: free market democracy, open competition, a robust private sector bound by rules of honesty and fairness, a secure safety net, and equal opportunity for all under a limited constitutional government of popular consent.

How extreme — like a Fourth of July picnic.

● Ryan would cut spending over the next decade by $6.2 trillion from Obama’s budget. This would return Washington’s slice of the economy to its historical average, below 20 percent, rather than Obama’s 23 percent spending floor.

● Ryan would eliminate $2.3 trillion in tax hikes, including $800 billion avoided by repealing Obamacare.

● Ryan would combine hundreds of overlapping programs, scrap others, and reform some, such as Medicare. While leaving beneficiaries over age 55 untouched, Ryan’s plan would give future retirees funds to help them purchase their choice of health coverage, rather than one Washington-dictated plan. Similarly, instead of a single federal Medicaid model, governors and state legislators would use federal block grants to serve the diverse needs of poor people in, say, Arizona and Vermont.

“The U.S. government is not running sustained deficits because Americans are taxed too little. The government is running deficits because it spends too much,” Ryan’s plan continues. It adds, “Over the past 40 years, government revenue has averaged between 18 percent and 19 percent of GDP. This level has generally been compatible with prosperity, even though there is broad agreement that the structure of the tax code should be simplified and made more conducive to economic growth, high wages, and entrepreneurship.”

Hence, the Path closes deductions and loopholes and lowers top individual and corporate taxes to 25 percent. This outright tax relief would end America’s 35 percent business levy, the industrial world’s highest.