Pennsylvania secretary of state: "Elections have never been called on election night"

Pennsylvania Secretary of State Kathy Boockvar reminded viewers on NBC's "Meet the Press" that "elections have never been called on election night," because service members overseas have until a week after Election Day to cast ballots in certain states.

The state of play: Boockvar said the state's election results will likely take longer to come in than usual, after anchor Chuck Todd noted that some counties in Pennsylvania will not begin counting mail-in ballots until the Wednesday after Election Day.

• Boockvar said she expects the final count, including mail-in and absentee ballots "to be counted within a matter of days" after Election Day.

Why it matters: President Trump has tried to cast doubt over election results that come in after Tuesday night, tweeting, "The Election should end on November 3rd., not weeks later!"

• But, but, but: "Americans are accustomed to knowing who won on election night because news organizations project winners based on partial counts, not because the counting is actually completed that quickly," the New York Times notes.

Be smart: Boockvar reassured voters that mail-in ballots will be counted if they are postmarked by Election Day and received by 5pm on Nov. 6.

• "Ignore the lawsuits, ignore the hype. Get your ballots in today."

Go deeper: Dem group warns of apparent Trump Election Day landslide