Most Democrats are being cautious about whether President Donald Trump might have obstructed justice in the Russia investigation and his dealings with fired FBI chief James Comey. Obstruction is a serious and complicated matter.

But the top Democrat on the Senate Judiciary Committee says it's a question worth examining.

Sen. Dianne Feinstein of California wants the committee to investigate ''all matters related to obstruction of justice and use its subpoena authority if necessary.''