You can find today's letter here. Among other things, the Speaker's note says it is "essential [that the President] address on what basis any use of force would be legally justified and how the justification comports with the exclusive authority of Congressional authorization of Article I of the Constitution."
The Speaker also puts forth fourteen additional questions, namely:
What standard did the Administration use to determine that this scope of chemical weapons use warrants potential military action?
Does the Administration consider such a response to be precedent-setting, should further humanitarian atrocities occur?
What result is the Administration seeking from its response?
What is the intended effect of the potential military strikes?
If potential strikes do not have the intended effect, will further strikes be conducted?
Would the sole purpose of a potential strike be to send a warning to the Assad regime about the use of chemical weapons? Or would a potential strike be intended to help shift the security momentum away from the regime and toward the opposition?
If it remains unclear whether the strikes compel the Assad regime to renounce and stop the use of chemical weapons against the Syrian people, or if President Assad escalates their usage, will the Administration contemplate escalatory military action?
Will your Administration conduct strikes if chemical weapons are utilized on a smaller scale?
Would you consider using the United States military to respond to situations or scenarios that do not directly involve the use or transfer of chemical weapons?
Assuming the targets of potential military strikes are restricted to the Assad inner circle and military leadership, does the Administration have contingency plans in case the strikes disrupt or throw into confusion the command and control of the regime’s weapons stocks?
Does the Administration have contingency plans if the momentum does shift away from the regime but toward terrorist organizations fighting to gain and maintain control of territory?
Does the Administration have contingency plans to deter or respond should Assad retaliate against U.S. interests or allies in the region?
Does the Administration have contingency plans should the strikes implicate foreign power interests, such as Iran or Russia?
Does the Administration intend to submit a supplemental appropriations request to Congress, should the scope and duration of the potential military strikes exceed the initial planning?