If the President and Vice President died (lets say hypothetically in a plane crash)

[Nottingham89]

Who would take there place in the US Government?

[ABerrant]

The US Constitution did not make specific mention of the Chief Justice as possible successor; the provision (Article II, Section 1, Clause 6) was for the Office to devolve to the Vice President, and that any further devolution would be to any Officer selected by Congress to act as President.

The First Congress (1791) saw an impasse on the proposed Officers (including that of the Chief Justice) to be included within the line of succession.

The Second Congress (1792) saw the Senate pass the Presidential Succession Act, placing in line of succession its President Pro Tempore, followed by the House Speaker. Later Acts have extended and refined the line of succession to the present.

The chronology of the line of succession may be viewed here...
http://www.doctorzebr...prez/a_succession.htm

BTW The Secretary of Agriculture is 9th in line.

[jno]

"It's enshrined in American culture that anyone should be able to make it to President ............ even Fred Flintstone"

Only if born in America. (This restriction doesn't apply to any other job, as far as I know.) That's why Schwarzenegger could never have made it.

[ABerrant]

"This restriction doesn't apply to any other job, as far as I know."

Likewise, eligibility for Vice-Presidency does not extend beyond natural-born citizens by virtue of the Twelfth Amendment...

'But no person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States.'

[BagPussAA]

Although, as previously stated, the President and VP would not travel together for this reason, they both have to be present for the State of the Union address which is why it is mentioned in the West Wing about the Sec. of Agriculture. Someone in the line of succession has to be absent from the State of the Union address, just in case the Capitol Building explodes and everyone else is killed.