What’s the one initiative Sen. Ted Cruz would pursue as president to help ordinary Americans?

That’s the question MSNBC host Joe Scarborough posed to the Texas Republican last week on “Morning Joe.” Cruz discussed the need for tax reform and his support for a flat tax allowing everyone to file their taxes “on a postcard.”

Cruz said he’d be willing to compromise in the style of President Reagan in an effort to implement a “low and simple” tax:

A lot of folks like to caricature me as someone who will never compromise. One person who has never said that is me. I mean, I’ve said from the beginning, my attitude on compromise is the same as Reagan’s. Reagan asked what do you do if they offer you half a loaf? Answer: You take it and then you come back for more.

Cruz said he would accept reform that would broaden the base of taxpayers, lower rates and simplify the code.

During his “Morning Joe” appearance, Cruz stood by his decision to sign a letter drafted by Sen. Tom Cotton, R-Ark., to the leaders of Iran regarding the role Congress plays in treaties and other agreements with foreign nations.

Co-host Mika Brzezinski repeatedly questioned Cruz about whether he and the 46 other Republican senators who signed the letter were “interfering” with President Obama’s negotiations, and called the letter “extremely destructive.”

“Is it your position that it’s inappropriate for the Congress to rein in the president on foreign policy?” Cruz asked Brzezinski.

Cruz said the letter was consistent with the constitutional role of the Senate, and was intended to “stop a bad deal” and to “defend the Constitution.”

“We don’t have a supreme leader like Iran does,” said Cruz. “We have checks and balances. And if you want to make law in this country, you need both the president and Congress. This is a unilateral president. That’s an enormous problem.”

Cruz argued that it was Obama’s penchant for acting unilaterally that made the letter “necessary”:

If we actually had negotiators that were trying to defend our national security, if anything the letter would help them because what the letter makes clear is for any deal to be binding, it has to go through Congress. And, Mika, the letter should not have proven necessary if we didn’t have a president like Barack Obama who routinely tries to circumvent Congress and the Senate.

When Brzezinski asked if he regretted signing the letter, Cruz responded:

“I would sign it and as John Hancock said, I would sign it in large print. The ayatollah wouldn’t need his reading glasses to read the signature.”

Cruz, fresh off of a visit to New Hampshire, also addressed the controversy stirred by some media outlets over the reaction of a 3-year-old girl in the audience when Cruz, discussing “the Obama-Clinton foreign policy,” used the metaphor “the whole world is on fire.”

“The world is on fire?” little Julie Trant asked.

Cruz assured the girl that people—such as her mother—were working to make the world better.

The little girl’s mother, Michelle Trant, a self-described Cruz supporter, called into WRKO Radio to say she was distressed by media accounts and that her daughter isn’t scared of Cruz.

Trant said she explained to her daughter that, like a fireman, Cruz “is the one that will put this fire out.” She added that Julie now sees the senator as a “hero.”

Cruz also appeared on “Late Night with Seth Meyers,” where Meyers asked him about climate change, same-sex marriage and why anyone would want to visit New Hampshire in March.