The quote below comes from the war powers resolution:
the president in every possible instance shall consult with congress before introducing united states armed forces into hostilities or into situation where imminent involvement in hostilities is clearly indicated by the circumstances, and after every such introduction shall consult regularly with the congress until united states armed forces are no longer engaged in hostilities or have been removed from such situations.
how did the vietnam war contribute to passage of this resolution?
it showed republicans that democrats were not committed to containment strongly enough.
it made it seem as though the president had broken the law.
it demonstrated the consequences of giving the president too much power over the military.
it made members of congress question the need for continuing to give the military a large budget.

Best

The Vietnam War demonstrated the consequences of giving the president too much power over the military.

Explanation:

The War Powers Resolution gave Congress (the legislative branch) power over whether to continue fighting a war, limiting the power fo the President to do so by his own authority.

Passed in 1973 over the veto of President Richard Nixon, the War Powers Resolution blocks presidents from continuing the pursuance of a war without Congress's approval.  Congress must be notified within 48 hours if troops are deployed, and troops cannot remained deployed beyond 60 days without approval from Congress.

The US Constitution leaves some tension in place between the legislative and executive branch when it comes to the country's involvement in war.  Article I of the Constitution gives Congress the power to declare war.  But Article II names the President the Commander-in-Chief, and presidents frequently have understood that role as containing the authority to deploy US forces without first getting congressional approval.  The War Powers Act requires the President to notify Congress of troop deployments and limits the length of time troops can be deployed without Congressional approval.

Some examples of primary source formats include:
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scrapbooks.
published books, newspapers and magazine clippings published at the time.
government publications.
oral histories.