WASHINGTON (AP) — Donald Trump confidant Roger Stone may be accused of lying and tampering with witnesses, but it's equally notable what he's not charged with: colluding with the Kremlin in a grand conspiracy to help Trump win the presidency in 2016.

The case is the latest in a series brought by special counsel Robert Mueller that focuses on cover-ups but lays out no underlying crime. It's a familiar pattern in Washington, where scandals from Watergate to Iran-Contra and Whitewater have mushroomed into presidency-imperiling affairs due to efforts to conceal and mislead.

In the Russia investiga...