Sarah Boltuck's senior year at Walt Whitman High School in Bethesda was transformed by a rejection letter -- not from a college, but from the Montgomery County Board of Elections.

It said she could not vote in the February primary because she was not yet 18. Boltuck thought differently. She fought it all the way to the state elections board and the attorney general's office, and she won.

Last month, Boltuck, along with her father and a sympathetic state senator, persuaded Maryland's top legal minds to restore the right of suffrage to at least 50,000 teens who will turn 18 between the Feb. 12 primary and the Nov. 4 election.

"I thought that was one of my rights as a citizen of Maryland," said Boltuck, who will be 18 in July. "I had assumed that when I registered to vote, it'd be no problem."

She called attention to a little-noticed change in interpretation of state law. Maryland was one of nine states, including Virginia, that allowed 17-year-olds to vote in primaries if they reached 18 by the general election. (The District does not.) But the Maryland State Board of Elections quietly halted the practice in December 2006 in response to a state court ruling.

Maryland's primary will be held a week after Super Tuesday, in an election "where generational politics is the fault line," said Jamie B. Raskin, a constitutional law scholar who represents Silver Spring and Takoma Park in the Maryland Senate. Boltuck and her friends at Whitman are part of an age bracket unusually energized this election cycle, particularly in support of Boltuck's candidate, Democrat Barack Obama.

"People just really want to get their voice heard," she said between sips of mocha at a cafe near her Bethesda home.

Obama has been courting young voters. His first public campaign stop in Maryland, for example, was an October visit to Prince George's Community College.

Young voters seem to be responding. They figured prominently in Obama's Iowa victory and strong second-place New Hampshire showing. A majority of Democratic voters ages 17 to 29 chose Obama in Iowa, and a majority of 18- to 24-year-olds picked him in New Hampshire, the largest share of voters in any age group to back a single candidate of either party, according to CNN entrance and exit polls. On the Internet site Facebook, a mecca for high school and college students, the largest group devoted to Obama has more than 400,000 members.

"That identification with younger voters is not by accident," said David Paulson, communication director of Maryland's Democratic Party.

Boltuck wanted to vote for Obama badly enough to launch, along with her father, a two-person lobbying campaign late last year. They tried to drum up news coverage. When that failed, Richard Boltuck submitted a letter to the editorial page of The Washington Post. It was published Dec. 2.

Some students in Anne Arundel County saw the letter and launched a Facebook group called "I'll be 18, so why can't I vote in my primary election?" More than 300 people joined.

"Despite what adults may think, 17-year-olds are not only ready to vote but are extremely passionate about the entire election," said Natalie Franke, one of the group's administrators, in an e-mail. She said she found out she had lost the right to vote from her AP Government teacher at Archbishop Spalding High School in Severn.

For decades, election boards had allowed Maryland residents to register at 17 under a state statute that said voters must be 18 by the general election. The law was read to mean a 17-year-old could vote in a primary. But the interpretation changed with a December 2006 ruling of the Maryland Court of Appeals. The ruling said primary and general elections should follow the same rules, including the one that says all voters must be 18. Election officials stopped registering 17-year-olds.

"Everybody was just getting rejection letters," Sarah Boltuck recalled.

Richard Boltuck, an economic consultant, contacted FairVote, a voting rights advocacy group in Takoma Park. The group put him in touch with Raskin. A strategy was conceived.

Raskin approached Maryland political party officials, who have authority over their own primary elections. Each party made a rule change that allowed 17-year-olds to vote in their primaries. Raskin reasoned that those rules, protected by the First Amendment, trumped the earlier state court ruling. He made the case to Attorney General Douglas F. Gansler in a Dec. 17 letter.

Gansler agreed. On Dec. 20, the state election board moved to restore the voting rights.

The haste with which the issue was resolved reflected both the strength of Raskin's argument and the political reality that no one "wanted to be on the wrong side" of a decision to narrow teen voting rights, said Robert Richie, executive director of FairVote.

Seventeen-year-olds can now vote in the primary on all but nonpartisan matters, which remain restricted to them because they fall outside the authority of the political parties. That means Boltuck cannot vote, oddly enough, on candidates for her own county school board.

Raskin has submitted a bill in the Maryland Senate that would amend the state Constitution to restore full voting rights to 17-year-olds. A lawsuit filed last week by a Frederick parent seeks the same end.

The focus now is to spread the word and register as many teens as possible by tomorrow's deadline.

About 8,000 Marylanders who will turn 18 by Election Day have registered to vote, half of them in the past month, according to state election officials. Letters have gone out to everyone who registered under the old rules to tell them they can now vote in the primary. Census data suggest upwards of 50,000 Maryland residents fall in the nine-month age range.

An informal survey of local school systems a few examples of coordinated effort. High schools in St. Mary's County distributed literature on the new rules in 12th-grade social studies classes. Democratic and Republican clubs in Calvert County visited each high school at lunchtime to register eligible 17-year-olds. At Einstein High School in Montgomery County, student Democrats registered 85 students in a single day by taking forms to English classes. Elly Shaw-Belblidia, a Democratic volunteer, led a team that visited several other Montgomery schools.

"It's frustrating," she said, "that we have so little time."