During Nixon's presidency, United States officials attempted to prevent Allende's election by financing political parties aligned with opposition candidate Jorge Alessandri and supporting strikes in the mining and transportation sectors. After the 1970 election, the Track I operation attempted to incite Chile's outgoing president, Eduardo Frei Montalva, to persuade his party (PDC) to vote in Congress for Alessandri. Under the plan, Alessandri would resign his office immediately after assuming it and call new elections. Eduardo Frei would then be constitutionally able to run again (since the Chilean Constitution did not allow a president to hold two consecutive terms, but allowed multiple non-consecutive ones), and presumably easily defeat Allende. The Chilean Congress instead chose Allende as president, on the condition that he would sign a "Statute of Constitutional Guarantees" affirming that he would respect and obey the Chilean Constitution and that his reforms would not undermine any of its elements.