Marijuana is about to become legal in Washington, but the idea of smoking pot in the shadow of the Capitol has some conservative lawmakers fuming.
Legalisation follows overwhelming support in November for a voter initiative to allow the possession, but not sale, of small amounts of pot by adults in the District of Columbia from midnight (local time).
Three states - Colorado, Washington and, since Tuesday, Alaska - already allow recreational pot use, with Oregon set to follow in July.
"Residents spoke loud and clear when they voted to legalise small amounts of marijuana in the District of Columbia," Mayor Muriel Bowser has said.
But since the District of Columbia is not a state, and since marijuana remains illegal under federal law, some Republican lawmakers are talking tough.
"If you decide to move forward ... You will be doing so in knowing and wilful violation of the law," said Representative Jason Chaffetz in a letter Tuesday to the newly elected mayor.
Chaffetz chairs the House Oversight and Government Reform Committee, which oversees legislative matters in Washington -- the only Western capital whose residents are constitutionally denied a voting representative in their national legislature.
"You can go to prison for this," Chaffetz, an young and ambitious Republican from Utah with Tea Party credentials, added in a Washington Post interview.
"We're not playing a little game here."
Only three times in four decades has Congress overturned a municipal law in Washington, whose residents favour the Democratic Party so strongly that the Republicans don't bother contesting many local elected positions.
Well aware of the fine line that the growing district of 650,000 is walking, the city government has tied plenty of strings to its local marijuana law.
Adults can possess no more than two ounces of pot, enough to roll about 80 cigarette-sized joints, and grow up to six cannabis plants at home.
The sale of pipes, bongs and rolling papers will be permitted -- but the buying and selling of marijuana will not.
"Home use. Home-grown," is the buzz phrase.
However, under the federal Controlled Substances Act, marijuana is not only illegal, but ranked on a par with heroin and LSD as one of the most dangerous illicit drugs around.
