WASHINGTON (AP) — Senate Minority Leader Harry Reid's decision to retire has sparked a feud between the No. 2 and No. 3 Senate Democrats.

Dick Durbin of Illinois — the No. 2 — and Chuck Schumer of New York — the No. 3 — are not vying over who replaces Reid. Schumer has already locked that up, with Durbin and Reid assenting.

Their disagreement centers on whether or not Schumer promised to back Durbin to hang onto his current job as whip. Durbin says Schumer did. Schumer denies it.

Democrats hoped to avoid a messy leadership struggle. Yet it's also unsurprising, given that Reid's retirement next year creates the first opening in the top ranks of Senate Democratic leadership in a decade.