House Republican leaders in Annapolis issued a statement saying they are "troubled" by Dwyer's behavior, while House Speaker Michael E. Busch said the legislature's ethics committee would defer possible action until police are done investigating the accident. The committee has the authority to recommend sanctions ranging from reprimand to expulsion.
"If the evidence proves to be correct, that he was at fault and that his blood alcohol is what he reported it to be, he should absolutely step down," said Don Murphy, a Republican strategist.
"He'll no longer have any credibility in the legislature generally, or on the Judiciary Committee. That is where these laws are made," Murphy said.
Dwyer, 54, a three-term Republican from Anne Arundel County, admitted Thursday that his blood-alcohol level was .20 percent, more than twice the legal limit, when the accident occurred. An aide said the delegate learned the test result from the staff at Maryland Shock Trauma Center, where he was flown after the accident.
The lawmaker was discharged from the hospital Thursday evening after holding a brief news conference during which he asked for forgiveness and admitted to having been drunk.
Until Wednesday's accident, Dwyer had appeared to have a smooth path to re-election in 2014. He recently moved to Pasadena, putting him in a heavily Republican district redrawn this year by the General Assembly. He also had expressed interest in running for the state Senate seat currently occupied by Republican Bryan Simonaire.
Now, either goal would be much more difficult to achieve, political experts say.
"It is possible that this is the end of his political career," said Donald F. Norris, who chairs the public policy department at the University of Maryland, Baltimore County.
"He comes from a very conservative constituency," Norris said. "I can't image that his constituents have a very high tolerance for their elected officials being drunk and hurting other people."
The Maryland Natural Resources Police investigation into the accident could take weeks to complete, officials said. Some boating offenses are misdemeanors and others could be categorized as felonies. Lawmakers who are convicted of felonies or crimes of "moral turpitude" must step down, but they are not barred from running again once their term is up.
Busch said in a statement that "as is typically the case" when a lawmaker is under criminal investigation, the Joint Committee on Legislative Ethics "will defer any action until the conclusion of the judicial process."
Depending on the outcome of the investigation, Dwyer also could face a civil suit from those who were injured in the accident, said Todd Eberly, a political scientist at St. Mary's College in Southern Maryland.
"It is a hard thing for someone to recover from," Eberly said of the accident. "It suggests a degree of irresponsibility.
"I would guess that forgiveness is always possible, but this is the kind of thing that causes people to question your character. Rightly or wrongly, it makes people question your judgment," Eberly said.
Dwyer is best known in Annapolis for his vocal opposition to same-sex marriage. He has argued that legalizing it would adversely affect young children who would be taught about homosexuality in schools.
Gay-rights groups quickly spread the news of the accident. "Lawmaker who thinks gays a threat to children crashes boat into children" was the headline on an article about the incident in Gay Star News, a national newsletter.
In 2010, Dwyer initiated articles of impeachment against Democratic Attorney General Douglas M. Gansler after Gansler issued an opinion that Maryland should recognize same-sex unions performed elsewhere.
This year, Dwyer pledged to devote all of his energy to defeating Gov. Martin O'Malley's bill to legalize same-sex marriage. The General Assembly approved the law, which opponents have petitioned to referendum in November.
Though combative on the House floor, Dwyer offered conciliatory words at the end of the emotional same-sex marriage debate.
"I know all of you expect me to get up here and go into a tirade," he said on the House floor in February before casting his "no" vote. "I will be forever grateful to my friends on the other side of the issue who have extended their hand."
He also expressed confidence in the referendum process, saying if voters accept the law, "Who am I to stand in the way?"