(New York Times) WASHINGTON — President Trump’s proposal to slash domestic spending in order to preserve the two biggest drains on the federal government — Social Security and Medicare — has set up a battle to determine who now controls the Republican Party’s ideology.

The outcome could map the course of major challenges to come, including a revision of the tax code, a huge increase in infrastructure spending and any effort to balance the budget.

Since the start of his insurgent campaign, Mr. Trump has opposed his party’s long-held positions on a range of policies, including free trade, how to deal with Russia and the future of government entitlement programs.

Mr. Trump’s budget blueprint — which is expected to be central to his address to Congress on Tuesday night — sets up a striking clash with the House speaker, Paul D. Ryan, who has made a career out of pressing difficult truths on federal spending. For years, Mr. Ryan has maintained that to tame the budget deficit without tax increases and prevent draconian cuts to federal programs, Congress must be willing to change, and cut, the programs that spend the most money — Social Security, Medicare and Medicaid.

But Mr. Trump, in a dogged effort to fulfill his campaign promises, has turned that logic on its head in the budget outline he is expected to present to Congress this week. That blueprint would make good on his promise to increase spending on the military and law enforcement by $100 billion over the next 18 months. And it would extract all of the savings he can from the one part of the budget already most squeezed, domestic discretionary spending, potentially decimating programs in education, poverty alleviation, science and health.

“For Paul Ryan, this seems to be the opportunity he has been waiting for and working for for years,” said Douglas Elmendorf, the recently departed director of the Congressional Budget Office and current dean of Harvard’s John F. Kennedy School of Government. “But Paul Ryan’s budget plans with cuts to Social Security and Medicare are not that popular with most voters, and what helped elect Donald Trump was the promise not to cut benefits and programs, and that is an unresolved tension.”

Continue Reading: Trump and Paul Ryan Head for a Clash Over the Budget, and Ideology – The New York Times