In an unusual departure from precedent, Majority Leader Trent Lott said Monday that hotly contested campaign finance legislation that cleared the Senate last month has not been sent to the House.

"I'm not going to send it over until the House acts" on the issue, Lott, R-Miss., told reporters. The unusually long delay that may prompt Sen. John McCain, the measure's main sponsor, to seek an advisory vote of the full Senate.

Unless Lott relents, McCain said on NBC's Meet the Press on Sunday, "We're going to have to force a vote on a resolution this week, so they'll send the bill over to the House." McCain's proposal would be nonbinding, but its passage would serve as a direct challenge to the majority leader.

The bill, designed to curtail the influence of money in politics, passed the Senate on April 2, 59-41.

Federal law requires that any passed bill "shall be sent to the other house." It imposes no timetable, although it is customarily done within a few days.

The weekend's disclosure marks the second time in two weeks that word has surfaced that Lott, who voted against the campaign finance legislation, has gone to rule-bending lengths in the Senate.

Early this month he ordered the dismissal of the Senate parliamentarian, who interprets rules and precedents, in a dispute over an impending ruling on budget legislation.

According to McCain's office, of the 13 bills to clear the Senate this year, 11 have been sent to the House in an average of slightly more than five days.

The 13th bill, relating to securities fees, passed the Senate on March 22 and still has not been sent to the House.

The immediate impact of Lott's decision is to make it impossible for the House to act formally on the Senate-passed bill.

Beyond that, supporters of the legislation said during the day they weren't certain what practical impact it would have, since the House can always debate and vote on its own version.

Still, Rep. Christopher Shays, R-Conn., issued a statement that said Lott was "playing a reckless game that further highlights the need for campaign finance reform."

Lott's move was made public during the weekend by McCain, the Arizona Republican who is the driving force behind the legislation.

He said he may demand a vote on a provision that says the delay means the "will of the majority of the Senate, having voted in favor of campaign finance reform, is being unduly thwarted." It urges that the bill to be delivered to the House "without any intervening delay."

Lott, speaking with reporters during the day, reaffirmed his decision to delay until the House has acted, adding that he anticipates the House and Senate could then appoint a committee to seek a compromise.

Supporters of the legislation are hoping to avoid formal House-Senate compromise talks, fearing that a hostile GOP leadership would use them as an excuse to bury the legislation. They prefer to pass legislation in the House that could go directly back to the Senate for final approval.