WASHINGTON � With the death of Edward M. Kennedy, seven seats in the Senate have been opened since the last election or soon will be, the most in any one year in six decades.

Two of the vacancies resulted from the victory of Sens. Barack Obama and Joe Biden in the presidential election.

After that, Obama named two senators to the Cabinet � former Colorado Sen. Kenneth Salazar to Interior and former New York Sen. Hillary Rodham Clinton to State. Since then, two Republican senators, Mel Martinez of Florida and Kay Bailey Hutchison of Texas, have said they will leave office this fall, before their terms expire.

With the exception of the Kennedy seat, the other six have been or will be filled by people appointed by their state's governors.

FairVote, a nonpartisan group that promotes greater access to the political process, said that the departures of lawmakers means that four out of the five most populous states � Illinois, New York, Florida and Texas � and almost 27 percent of the U.S. population, will be represented by unelected senators.

There are calls for change in a replacement system that many say is not democratic. Critics point not only to the high number of vacancies but the manner in which some have been filled.

In Illinois, impeached former Gov. Rod Blagojevich faces charges that he tried to sell Obama's old seat. Roland Burris, the eventual appointee, has not been implicated in the scandal but has been tainted by the controversy and will not be running for a full term.

New York endured a media frenzy as Caroline Kennedy announced her desire to replace Clinton, and then eventually withdrew her name after a lackluster effort to prove she was qualified. Gov. David Paterson then appointed Kirsten Gillibrand, a little-known congresswoman from upstate New York.

Delaware Gov. Ruth Ann Minner tapped Ted Kaufman, a former Biden aide and law school professor who had never held elected office, to hold Biden's seat until next year, when Biden's son Beau, the state attorney general, returns from duty in Iraq and is expected to contend for the Senate seat.

The Congressional Research Service said there have been 184 Senate appointments since 1913, when the 17th Amendment became effective, replacing the election of senators by state legislatures by direct popular votes.

Of those, seven were the widows of senators, two the spouses of the governor, three the sons of senators and one the daughter of a governor.

Frank Murkowski's appointment of his daughter Lisa in 2002 after he left the Senate to successfully run for governor of Alaska prompted legislation and a voter referendum that require quick special elections, although with differing provisions on the governor's authority to make temporary appointments.

Sen. Russ Feingold, D-Wis., joined by Sens. John McCain, R-Ariz., and Mark Begich, D-Alaska, has introduced a constitutional amendment requiring elections for Senate vacancies � the Constitution already requires House vacancies to be filled by elections � and end what Feingold called "an antidemocratic process that denies voters the opportunity to determine who represents them in the U.S. Senate."

Rep. David Dreier of California, the top Republican on the Rules Committee, and Judiciary Committee chairman John Conyers, D-Mich., have introduced an identical proposal in the House.

The Feingold measure cleared a Senate Judiciary subcommittee in early August, but faces the very high hurdles that defeat almost all efforts to alter the Constitution. Senate Majority Leader Harry Reid, D-Nev., has made clear he doesn't support it, saying at a news conference that he did not favor "dictating to a state what they should do."

If that fails, House Republicans led by Rep. Aaron Schock of Illinois, have proposed a measure that would allow governors or state legislatures to make interim appointments but require special elections within 90 days of a vacancy.

Special elections have their detractors, who argue that they are too expensive, take too much time to organize and are characterized by low voter turnouts that are not particularly representative of democracy at work.

The Democratic-controlled legislature in Kennedy's home state of Massachusetts in 2004 changed state law to require special elections and prevent then Gov. Mitt Romney, a Republican, from naming a replacement had Sen. John Kerry won the presidency.

Just days before his death Kennedy asked state lawmakers to revert to the old system so that the current Democratic Gov. Deval Patrick could name a successor if Kennedy had to leave office, avoiding the gap of up to five months between the vacancy and the holding of a special election and ensuring that Democrats wouldn't lose a vote crucial to passing the health care legislation that Kennedy was so passionate about.

The constitutional amendments are S.J. Res. 7 and H.J. Res. 21. The Schock bill is H.R. 899.