If memory serves: The question of cognitive function in an aging Congress

Julian Zelizer: Sen. Dianne Feinstein's recent return to D.C. raised questions about her cognitive abilities and fitness for work.

He says a physician can't confirm or refute a cognitive decline diagnosis without a formal examination.

Zelizer says we should expect our politicians to be able to function as normal citizens.

He writes that 1.7 percent of Americans take antipsychotic medication, which is not exclusively prescribed psychosis.

Joel Zivot: Congress consists of a range of Americans with mental and physical health problems.

He says it's possible that at any time, maybe 20 to 30 members of Congress are drunk.

Zivot says it would be interesting to have breathalyzers on Capitol Hill, just to be sure all voting members are clear-headed.

In D.C., consumption of marijuana is not permitted in public places but permitted in privacy of one’s home.