WASHINGTON — President Donald Trump fulfilled a major campaign promise Tuesday, proposing a $4.1 trillion budget plan that would upend Washington in a big way. But he drew rebukes, even from some Republican allies, for the plan's jarring, politically unrealistic cuts to the social safety net for the poor and a broad swath of other domestic programs.The budget, Trump's first as president, combines his spending plan for the upcoming 2018 fiscal year with a promise to balance government books after a decade, relying on aggressive cuts, a surge in economic growth — and a $2 trillion-plus accounting gimmick."Through streamlined government, we will drive an economic boom that raises incomes and expands job opportunities for all Americans," Trump declared in his budget message."Basically dead on arrival," opined the Senate's No. 2 Republican, John Cornyn of Texas.The proposal reflects a conservative vision of smaller government, a drastic rollback of programs for the poor and disabled to prod them into the workforce and a robust hike for the military and border security.