A Paul Ryan Two-fer

"I'm Paul Ryan and I approved this message."

Or perhaps he should say "messages."

Everyone knows Rep. Paul Ryan (R-WI) is running.

Not just for vice president. But in his Congressional district this fall as well.

In other words, Wisconsin voters have the chance to vote for Ryan - or against Ryan - twice.

This isn't new.

In 1960, then-Senate Majority Leader Lyndon B. Johnson (D-TX) found himself on the ballot twice as well. Once for re-election to the Senate. And once as President Kennedy's running mate.

Johnson's Senate opponent, John Tower (who Texas voters later elected to the seat) used the campaign slogan, "Double your pleasure, double your fun, vote against Johnson two times, not one."

Always ambitious, it was actually Johnson who famously engineered a change in Texas law so he could appear on the ballot twice. By running for both positions, LBJ had a safety net in case Kennedy lost the election.

Johnson won both contests in 1960, resigned his Senate seat and became vice president. Tower didn't succeed Johnson immediately in the Senate but won a special election soon thereafter.

LBJ wasn't the first politician to win multiple races simultaneously.

In late 1880, James Garfield faced even more convoluted conundrum. To this day, Garfield is the only person to serve as a member of the House while being a senator-elect and president-elect at the same time.

The Constitution is silent on banning candidates from running for multiple positions during the same election cycle. States are left to create their own rules on the issue.

Figures such as the late-Sen. Lloyd Bentsen (D-TX), Sen. Joe Lieberman (I-CT) and even Vice President Biden found themselves in similar situations as the one Ryan is in now.

Bentsen was Michael Dukakis's running mate in 1988 and up for re-election to the Senate. Lieberman was Gore's running mate in 2000 and also standing for re-election. Biden was on the ballot in Delaware for another Senate term in 2008 when he was President Obama's number two.

In Wisconsin, two candidates are not permitted to appear on the ballot twice with the exception of presidential and vice presidential candidates.

Voters re-elected Ryan to his Congressional seat in 2008 even though President Obama carried the district.

If Ryan wins both his House seat this fall and voters elect Mitt Romney as president, Wisconsin will hold a special election to fill Ryan's House seat. If Ryan loses the national election, the Wisconsin Republican has the security of knowing he go back to his old job - barring any sort of upset.

- Juliegrace Brufke contributed to this report.