WASHINGTON — Paul Ryan traveled a perilous route to political stardom. While other lawmakers nervously whistled past trillion-dollar deficits, fearing to cut popular programs, he waded in with a machete and a smile.

Ryan wants to slice away at Medicare, food stamps and virtually every other government program but the military.

Democrats, led by President Barack Obama, have made him their budget boogeyman. Even many fellow Republicans were reluctant to follow him at first.

But Ryan has become a hero to deficit hawks. Twice now, the Republican-led House has embraced his austere budget plans. And in these tea party-infused, economically bleak days, Ryan’s fiscal ideas have moved into the Republican Party’s mainstream, just in time to be tested in the 2012 elections.

As Mitt Romney’s vice presidential pick, the GOP’s boisterous budget outrider is now its loudest voice on taxes and spending.

Romney calls his running mate an intellectual leader of the party with a “bold and exciting” budget plan. But Romney also has been careful to note, without elaboration, that he doesn’t necessarily agree with all of Ryan’s ideas.

Indeed, some of the Wisconsin congressman’s previous suggestions — on the shelf since he ascended to the chairmanship of the House Budget Committee in 2011 — were politically riskier. They included privatizing Medicare and part of Social Security and ending taxes on interest and investment income, meaning some wealthy investors like Romney might owe virtually no income taxes. Ryan has backed off those proposals, but he still stirs controversy.

For Ryan, it all starts with putting the brakes on the nation’s out-of-control debt. For years he’s been wielding colorful charts and graphs to sound the alarm about annual deficits topping $1 trillion.

In March, the House passed a federal budget outline based on Ryan’s plans that would protect the Pentagon but reduce spending on almost everything else, including roads, farm programs, health care, research and education. It aims to whittle the annual deficit to about $287 billion in 2022. That compares with a $704 billion deficit projected for Obama’s budget plan. (The House bill is a non-starter in the Democratic-controlled Senate.)

A majority of House Republicans actually voted for even deeper cuts. And a few Democrats joined in passing the Ryan plan, which over the next decade would spend $5.3 trillion less than Obama wants while cutting taxes by $2 trillion more.