The last President to shrink the NSA, CIA, etc was Jimmy Carter.
It was also under the Carter administration - and under Democratic majorities in both the House and Senate - that the FISA Act was passed, which is what eventually led to all this secret surveillance.
No, the FISA Act restricted warrantless domestic surveillance by criminalizing it in response to abuses, largely by the Nixon Administration, before there was any statute law addressing the issue. What legally opened the door for subsequent warrantless surveillance was the passage of the FISA Amendments Act of 2008 which loosened the FISA restrictions to make legal what the Bush Administration had already been doing.
> In 2008, Democrats controlled both houses of Congress.
And neither of the major US parties (and especially not the Democratic Party, whose major factions include both a center-right faction and a moderate left faction) are unified cohesive parties with strong discipline as you might find in a multiparty parliamentary system; the FISA Amendments Act passed with every Republican that voted in either house (except one in the House) and a minority of Democrats on each house supporting it, and the majority of Democrats in each house opposing it.
> the FISA Act was passed, which is what eventually led to all this secret surveillance.
That's like saying speed limits led to to the problem of people driving fast. FISA was a set of limits put in place because the surveillance was already happening. Oversight where there was none prior.
It was also under the Carter administration - and under Democratic majorities in both the House and Senate - that the FISA Act was passed, which is what eventually led to all this secret surveillance.