When Massachusetts Republican Scott Brown scored an upset win to take the U.S. Senate seat formerly held by Sen. Edward M. Kennedy, former Gov. Robert L. Ehrlich Jr. called it a highly significant event in his thinking about whether he could retake Maryland's governor's mansion. That election, coupled with GOP wins in the Virginia and New Jersey gubernatorial races, made a Republican victory in blue Maryland seem a little more plausible; the electorate was clearly agitated and not playing by the conventional rules. Tuesday's elections — primaries in Kentucky and Arkansas and a primary and a special election in Pennsylvania — continued the theme of an anti-incumbent, anti-establishment wave across the nation, but their implications for Maryland are a little less clear. Here's why. • Kentucky: Political novice Rand Paul — the son of U.S. Rep. Ron Paul and a favorite of the tea party movement — easily beat Secretary of State Trey Grayson, who had the backing of the entire Republican establishment, including the state's senior senator, Mitch McConnell. Dr. Paul — an ophthalmologist — benefited from his father's name and fundraising network, but his message of smaller government, term limits and a balanced budget amendment catapulted him to victory. Like Senator Brown's victory, the election was a show of the grass-roots strength of the tea party movement and a repudiation of the status quo. What might that mean for Mr. Ehrlich? The tea party movement could cut either way for him. He is the poster child for the Maryland Republican establishment, and as governor, he didn't oversee a wholesale reduction in the size and scope of government. But he has been greeted warmly by the tea party here and has connections to its leadership in Maryland. Regardless, a Republican primary in Kentucky doesn't say much about how a general election will turn out in Maryland. • Arkansas: Two-term incumbent Sen. Blanche Lambert Lincoln faces a runoff against Lt. Gov. Bill Halter, who managed to hold her to under 50 percent of the vote. Is this a good sign or a bad sign for Maryland's chief incumbent Democrat, Gov. Martin O'Malley? Again, it could go either way. The Arkansas election certainly was evidence of anti-incumbent sentiment, but Mr. Halter ran to the left of Senator Lincoln and was buoyed by strong union and liberal activist support. Since Governor O'Malley doesn't face a challenge from his left and has already started picking up union support, it's hard to draw much of a lesson from this race. • Pennsylvania: Sen. Arlen Specter, who switched parties to run as a Democrat in hopes of holding his seat, had the backing of President Barack Obama and Gov. Ed Rendell, but that was no match for the anti-incumbent sentiment in Pennsylvania. He lost to Rep. Joe Sestak, a moderate Democrat who pitched his win as a victory over the establishment. This might suggest that Governor O'Malley will get less benefit from his ability to bring in Democratic Party stars to make his case. In 2006, he got a last-minute boost from former President Bill Clinton, who made appearances on Mr. O'Malley's behalf and recorded a television commercial for him. But those sorts of endorsements seem to hold less sway this year. Still, Mr. O'Malley still might get a boost from his ties to the Clintons and President Obama in driving up turnout from liberals and African-American voters, which will be a crucial factor in his success or failure. The only Tuesday election that Democrats can point to as an unmitigated good sign was the victory of Democrat Mark Critz over Republican Tim Burns in the special election to replace the late Rep. John Murtha in western Pennsylvania. The district is traditionally Democratic, but it actually went for Sen. John McCain in the 2008 presidential election and looked like a sure opportunity for a Republican pickup. Mr. Burns, a businessman, pitched his campaign as a rejection of the liberal agenda of House Speaker Nancy Pelosi, but rather than rejecting Washington, the district instead elected Mr. Critz, a former top aide to Mr. Murtha, who was himself a key Pelosi ally. It would be a mistake to think a special election in a rural district in Pennsylvania says too much about the general election prospects in Maryland, but it does belie the notion that Mr. Ehrlich might benefit from the kind of tailwind this fall that helped Mr. O'Malley in 2006. After Tuesday's elections, the contest in Maryland probably remains what it has been: a rematch between two well-known candidates that will be decided based on their campaigns, not national sentiment.